diff --git a/.github/workflows/cs.yml b/.github/workflows/cs.yml
new file mode 100644
index 0000000..a269994
--- /dev/null
+++ b/.github/workflows/cs.yml
@@ -0,0 +1,37 @@
+on:
+    pull_request:
+
+name: Coding Standards
+
+jobs:
+    phpstan:
+        name: PHP CS
+
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+
+            - name: Setup PHP
+              uses: shivammathur/setup-php@v2
+              with:
+                  php-version: 7.4
+                  tools: composer
+
+            - name: Get composer cache directory
+              id: composer-cache
+              run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+            - name: Cache dependencies
+              uses: actions/cache@v2
+              with:
+                  path: ${{ steps.composer-cache.outputs.dir }}
+                  key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+                  restore-keys: ${{ runner.os }}-composer-
+
+            - name: Install dependencies
+              run: composer install --prefer-dist
+
+            - name: PHP-CS-Fixer
+              run: vendor/bin/php-cs-fixer fix --dry-run -v
diff --git a/.github/workflows/static-analysis.yml b/.github/workflows/static-analysis.yml
new file mode 100644
index 0000000..31f3146
--- /dev/null
+++ b/.github/workflows/static-analysis.yml
@@ -0,0 +1,37 @@
+on:
+    pull_request:
+
+name: Static Analysis
+
+jobs:
+    phpstan:
+        name: PHPStan
+
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+
+            - name: Setup PHP
+              uses: shivammathur/setup-php@v2
+              with:
+                  php-version: 7.4
+                  tools: composer
+
+            - name: Get composer cache directory
+              id: composer-cache
+              run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+            - name: Cache dependencies
+              uses: actions/cache@v2
+              with:
+                  path: ${{ steps.composer-cache.outputs.dir }}
+                  key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+                  restore-keys: ${{ runner.os }}-composer-
+
+            - name: Install dependencies
+              run: composer install --prefer-dist
+
+            - name: PHPStan
+              run: vendor/bin/phpstan
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 0000000..1e78057
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,90 @@
+name: Unit Tests
+
+on:
+    push:
+        branches:
+            - master
+    pull_request: ~
+
+jobs:
+    unit-test:
+        name: Unit ( PHP ${{ matrix.php }} )
+        runs-on: ubuntu-latest
+
+        strategy:
+            fail-fast: false
+            matrix:
+                include:
+                    -   php: 7.2
+                    -   php: 7.3
+                    -   php: 7.4
+                    -   php: 8.0
+                    -   php: 8.1
+                    -   php: 8.2
+                    -   php: 8.3
+
+        steps:
+            -   name: Checkout
+                uses: actions/checkout@v3
+
+            -   name: Setup PHP
+                uses: shivammathur/setup-php@v2
+                with:
+                    php-version: ${{ matrix.php }}
+                    extensions: opcache
+                    tools: composer
+
+            -   name: Get composer cache directory
+                id: composercache
+                run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+            -   name: Cache dependencies
+                uses: actions/cache@v2
+                with:
+                    path: ${{ steps.composercache.outputs.dir }}
+                    key: ${{ runner.os }}-php-${{ matrix.php }}-composer-${{ hashFiles('composer.json composer.lock') }}
+                    restore-keys: ${{ runner.os }}-php-${{ matrix.php }}-composer-
+
+            -   name: Install dependencies
+                run: composer update
+
+            -   name: Run unit tests
+                run: vendor/bin/phpunit
+
+    lowest:
+        name: Unit ( PHP ${{ matrix.php }} + Lowest )
+        runs-on: ubuntu-latest
+
+        strategy:
+            fail-fast: false
+            matrix:
+                include:
+                    -   php: 7.2
+
+        steps:
+            -   name: Checkout
+                uses: actions/checkout@v2
+
+            -   name: Setup PHP
+                uses: shivammathur/setup-php@v2
+                with:
+                    php-version: ${{ matrix.php }}
+                    extensions: :xdebug
+                    tools: composer
+
+            -   name: Get composer cache directory
+                id: composercache
+                run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+            -   name: Cache dependencies
+                uses: actions/cache@v2
+                with:
+                    path: ${{ steps.composercache.outputs.dir }}
+                    key: ${{ runner.os }}-php-${{ matrix.php }}-composer-${{ hashFiles('composer.json composer.lock') }}
+                    restore-keys: ${{ runner.os }}-php-${{ matrix.php }}-composer-
+
+            -   name: Install dependencies
+                run: composer update --prefer-lowest --prefer-stable
+
+            -   name: Run unit tests
+                run: vendor/bin/phpunit
diff --git a/.gitignore b/.gitignore
index 3a9875b..ff6836c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,7 @@
 /vendor/
-composer.lock
+/composer.lock
+/vendor-bin/**/vendor
+/.php_cs.cache
+/src/compiled.php
+.idea
+.phpunit.result.cache
diff --git a/.php-version b/.php-version
new file mode 100644
index 0000000..5904f7a
--- /dev/null
+++ b/.php-version
@@ -0,0 +1 @@
+7.2
diff --git a/.php_cs b/.php_cs
new file mode 100644
index 0000000..0208b81
--- /dev/null
+++ b/.php_cs
@@ -0,0 +1,18 @@
+<?php
+
+$finder = PhpCsFixer\Finder::create()
+    ->in('src')
+    ->in('tests')
+    ->notName('compiled.php');
+
+return PhpCsFixer\Config::create()
+    ->setRules(
+        [
+            '@PSR1' => true,
+            '@PSR2' => true,
+            'array_syntax' => ['syntax' => 'short'],
+            'single_import_per_statement' => false,
+        ]
+    )
+    ->setFinder($finder)
+;
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 14ba5f4..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,36 +0,0 @@
-language: php
-
-sudo: false
-
-env:
-    - COMPOSER_OPTIONS="
-
-php:
-    - 7.1
-
-matrix:
-  fast_finish: true
-  include:
-    - php: 7.1
-      env:
-        - COMPOSER_OPTIONS="--prefer-lowest"
-    - php: 7.1
-      env:
-        - COMPOSER_OPTIONS="--prefer-stable"
-    - php: 7.2
-    - php: nightly
-  allow_failures:
-    - php: nightly
-
-cache:
-  directories:
-    - $HOME/.composer/cache/files
-
-before_install:
-  - composer self-update
-
-install:
-  - composer update -n "$COMPOSER_OPTIONS"
-
-script:
-    - vendor/bin/phpunit
diff --git a/README.md b/README.md
index d048312..3d9cc8a 100644
--- a/README.md
+++ b/README.md
@@ -4,12 +4,16 @@ Lodash-PHP is a port of the [Lodash JS library](https://lodash.com/) to PHP. It
 
 Lodash-PHP tries to mimick lodash.js as close as possible
 
+# Requirements
+
+Lodash-PHP requires minimum PHP 7.2+, but the latest version of PHP is always recommended.
+
 # Installation
 
 Install Lodash-PHP through composer:
 
 ```bash
-$ composer require solidworx/lodash-php
+$ composer require lodash-php/lodash-php
 ```
 
 # Usage
@@ -40,8 +44,12 @@ _::each([1, 2, 3], function (int $item) {
 - [Array](#array)
 - [Collection](#collection)
 - [Date](#date)
+- [Function](#function)
 - [Lang](#lang)
+- [Math](#math)
 - [Number](#number)
+- [Object](#object)
+- [Seq](#seq)
 - [String](#string)
 - [Util](#util)
 
@@ -50,10 +58,12 @@ _::each([1, 2, 3], function (int $item) {
 ### chunk
 
 Creates an array of elements split into groups the length of `size`.
-
 If `array` can't be split evenly, the final chunk will be the remaining
 elements.
 
+
+
+
 **Arguments:**
 
 @param array $array array The array to process.
@@ -85,6 +95,7 @@ Creates an array with all falsey values removed. The values `false`, `null`,
 
 
 
+
 **Arguments:**
 
 @param array $array The array to compact.
@@ -111,11 +122,13 @@ and/or values.
 
 
 
+
+
 **Arguments:**
 
 @param array $array The array to concatenate.
 
-@param mixed $values The values to concatenate.
+@param array<int, mixed> $values The values to concatenate.
 
 
 
@@ -131,10 +144,10 @@ Example:
 $array = [1];
 $other = concat($array, 2, [3], [[4]]);
 
-var_dump(other)
+var_dump($other)
 // => [1, 2, 3, [4]]
 
-var_dump(array)
+var_dump($array)
 // => [1]
 
 ```
@@ -147,11 +160,15 @@ determined by the first array.
 
 **Note:** Unlike `pullAll`, this method returns a new array.
 
+
+
+
+
 **Arguments:**
 
 @param array $array The array to inspect.
 
-@param array $values The values to exclude.
+@param array ...$values The values to exclude.
 
 
 
@@ -178,13 +195,17 @@ determined by the first array. The iteratee is invoked with one argument:
 
 **Note:** Unlike `pullAllBy`, this method returns a new array.
 
+
+
+
+
 **Arguments:**
 
 @param array $array The array to inspect.
 
-@param array $values The values to exclude.
+@param array<int, mixed> ...$values The values to exclude.
 
-@param callable $ iteratee The iteratee invoked per element.
+@param callable $iteratee The iteratee invoked per element.
 
 
 
@@ -196,8 +217,10 @@ Example:
 ```php
 <?php
  use function _\differenceBy;
+
 differenceBy([2.1, 1.2], [2.3, 3.4], 'floor')
 // => [1.2]
+
 ```
 ### differenceWith
 
@@ -208,11 +231,16 @@ is invoked with two arguments: (arrVal, othVal).
 
 **Note:** Unlike `pullAllWith`, this method returns a new array.
 
+
+
+
+
+
 **Arguments:**
 
-@param array $array The array to inspect.
+@param array<int, mixed> $array The array to inspect.
 
-@param array[] $values The values to exclude.
+@param array ...$values The values to exclude.
 
 @param callable $comparator The comparator invoked per element.
 
@@ -239,6 +267,9 @@ Creates a slice of `array` with `n` elements dropped from the beginning.
 
 **NOTE:** This function will reorder and reset the array indices
 
+
+
+
 **Arguments:**
 
 @param array $array The array to query.
@@ -272,9 +303,11 @@ drop([1, 2, 3], 0)
 ### dropRight
 
 Creates a slice of `array` with `n` elements dropped from the end.
-
 **NOTE:** This function will reorder and reset the array indices
 
+
+
+
 **Arguments:**
 
 @param array $array The array to query.
@@ -308,10 +341,12 @@ dropRight([1, 2, 3], 0)
 ### dropRightWhile
 
 Creates a slice of `array` excluding elements dropped from the end.
-
 Elements are dropped until `predicate` returns falsey. The predicate is
 invoked with three arguments: (value, index, array).
 
+
+
+
 **Arguments:**
 
 @param array $array The array to query.
@@ -330,9 +365,9 @@ Example:
  use function _\dropRightWhile;
 
 $users = [
-  [ 'user' => 'barney',  'active' => false ],
-  [ 'user' => 'fred',    'active' => true ],
-  [ 'user' => 'pebbles', 'active' => true ]
+[ 'user' => 'barney',  'active' => false ],
+[ 'user' => 'fred',    'active' => true ],
+[ 'user' => 'pebbles', 'active' => true ]
 ]
 
 dropRightWhile($users, function($user) { return $user['active']; })
@@ -342,10 +377,12 @@ dropRightWhile($users, function($user) { return $user['active']; })
 ### dropWhile
 
 Creates a slice of `array` excluding elements dropped from the beginning.
-
 Elements are dropped until `predicate` returns falsey. The predicate is
 invoked with three arguments: (value, index, array).
 
+
+
+
 **Arguments:**
 
 @param array $array The array to query.
@@ -364,14 +401,67 @@ Example:
  use function _\dropWhile;
 
 $users = [
-  [ 'user' => 'barney',  'active' => true ],
-  [ 'user' => 'fred',    'active' => true ],
-  [ 'user' => 'pebbles', 'active' => false ]
+[ 'user' => 'barney',  'active' => true ],
+[ 'user' => 'fred',    'active' => true ],
+[ 'user' => 'pebbles', 'active' => false ]
 ]
 
 dropWhile($users, function($user) { return $user['active']; } )
 // => objects for ['pebbles']
 
+```
+### every
+
+Checks if `predicate` returns truthy for **all** elements of `array`.
+Iteration is stopped once `predicate` returns falsey. The predicate is
+invoked with three arguments: (value, index, array).
+
+**Note:** This method returns `true` for
+[empty arrays](https://en.wikipedia.org/wiki/Empty_set) because
+[everything is true](https://en.wikipedia.org/wiki/Vacuous_truth) of
+elements of empty arrays.
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The array to iterate over.
+
+@param callable $predicate The function invoked per iteration.
+
+
+
+**Return:**
+
+@return bool `true` if all elements pass the predicate check, else `false`.
+
+Example:
+```php
+<?php
+ use function _\every;
+
+every([true, 1, null, 'yes'], function ($value) { return is_bool($value);})
+// => false
+
+$users = [
+['user' => 'barney', 'age' => 36, 'active' => false],
+['user' => 'fred', 'age' => 40, 'active' => false],
+];
+
+// The `matches` iteratee shorthand.
+$this->assertFalse(every($users, ['user' => 'barney', 'active' => false]));
+// false
+
+// The `matchesProperty` iteratee shorthand.
+$this->assertTrue(every($users, ['active', false]));
+// true
+
+// The `property` iteratee shorthand.
+$this->assertFalse(every($users, 'active'));
+//false
+
+
 ```
 ### findIndex
 
@@ -379,6 +469,7 @@ This method is like `find` except that it returns the index of the first element
 
 
 
+
 **Arguments:**
 
 @param array $array The array to inspect.
@@ -399,9 +490,9 @@ Example:
  use function _\findIndex;
 
 $users = [
-    ['user' => 'barney',  'active' => false],
-    ['user' => 'fred',    'active' => false],
-    ['user' => 'pebbles', 'active' => true],
+['user' => 'barney',  'active' => false],
+['user' => 'fred',    'active' => false],
+['user' => 'pebbles', 'active' => true],
 ];
 
 findIndex($users, function($o) { return $o['user'] s== 'barney'; });
@@ -427,6 +518,7 @@ of `collection` from right to left.
 
 
 
+
 **Arguments:**
 
 @param array $array The array to inspect.
@@ -447,9 +539,9 @@ Example:
  use function _\findLastIndex;
 
 $users = [
-  ['user' => 'barney',  'active' => true ],
-  ['user' => 'fred',    'active' => false ],
-  ['user' => 'pebbles', 'active' => false ]
+['user' => 'barney',  'active' => true ],
+['user' => 'fred',    'active' => false ],
+['user' => 'pebbles', 'active' => false ]
 ]
 
 findLastIndex($users, function($user) { return $user['user'] === 'pebbles'; })
@@ -462,6 +554,7 @@ Flattens `array` a single level deep.
 
 
 
+
 **Arguments:**
 
 @param array $array The array to flatten.
@@ -476,8 +569,10 @@ Example:
 ```php
 <?php
  use function _\flatten;
+
 flatten([1, [2, [3, [4]], 5]])
 // => [1, 2, [3, [4]], 5]
+
 ```
 ### flattenDeep
 
@@ -485,6 +580,7 @@ Recursively flattens `array`.
 
 
 
+
 **Arguments:**
 
 @param array $array The array to flatten.
@@ -510,6 +606,7 @@ Recursively flatten `array` up to `depth` times.
 
 
 
+
 **Arguments:**
 
 @param array $array The array to flatten.
@@ -543,6 +640,8 @@ from key-value `pairs`.
 
 
 
+
+
 **Arguments:**
 
 @param array $pairs The key-value pairs.
@@ -551,7 +650,7 @@ from key-value `pairs`.
 
 **Return:**
 
-@return object the new object.
+@return \stdClass the new object.
 
 Example:
 ```php
@@ -571,6 +670,8 @@ Gets the first element of `array`.
 
 
 
+
+
 **Arguments:**
 
 @param array $array The array to query.
@@ -602,6 +703,7 @@ offset from the end of `array`.
 
 
 
+
 **Arguments:**
 
 @param array $array The array to inspect.
@@ -635,6 +737,7 @@ Gets all but the last element of `array`.
 
 
 
+
 **Arguments:**
 
 @param array $array The array to query.
@@ -649,8 +752,10 @@ Example:
 ```php
 <?php
  use function _\initial;
+
 initial([1, 2, 3])
 // => [1, 2]
+
 ```
 ### intersection
 
@@ -661,9 +766,11 @@ determined by the first array.
 
 
 
+
+
 **Arguments:**
 
-@param array[] $arrays
+@param array ...$arrays
 
 
 
@@ -675,8 +782,10 @@ Example:
 ```php
 <?php
  use function _\intersection;
+
 intersection([2, 1], [2, 3])
 // => [2]
+
 ```
 ### intersectionBy
 
@@ -688,9 +797,10 @@ determined by the first array. The iteratee is invoked with one argument:
 
 
 
+
 **Arguments:**
 
-@param array[] $arrays
+@param array<int, mixed> ...$arrays
 
 @param callable $iteratee The iteratee invoked per element.
 
@@ -722,9 +832,11 @@ invoked with two arguments: (arrVal, othVal).
 
 
 
+
+
 **Arguments:**
 
-@param array[] $arrays
+@param array ...$arrays
 
 @param callable $comparator The comparator invoked per element.
 
@@ -752,6 +864,7 @@ Gets the last element of `array`.
 
 
 
+
 **Arguments:**
 
 @param array $array The array to query.
@@ -778,6 +891,7 @@ This method is like `indexOf` except that it iterates over elements of
 
 
 
+
 **Arguments:**
 
 @param array $array The array to inspect.
@@ -812,6 +926,7 @@ element from the end is returned.
 
 
 
+
 **Arguments:**
 
 @param array $array The array to query.
@@ -828,6 +943,7 @@ Example:
 ```php
 <?php
  use function _\nth;
+
 $array = ['a', 'b', 'c', 'd']
 
 nth($array, 1)
@@ -835,6 +951,7 @@ nth($array, 1)
 
 nth($array, -2)
 // => 'c'
+
 ```
 ### pull
 
@@ -845,11 +962,15 @@ for equality comparisons.
 **Note:** Unlike `without`, this method mutates `array`. Use `remove`
 to remove elements from an array by predicate.
 
+
+
+
+
 **Arguments:**
 
 @param array $array The array to modify.
 
-@param array $values The values to remove.
+@param array<int, string> $values The values to remove.
 
 
 
@@ -875,6 +996,9 @@ This method is like `pull` except that it accepts an array of values to remove.
 
 **Note:** Unlike `difference`, this method mutates `array`.
 
+
+
+
 **Arguments:**
 
 @param array $array The array to modify.
@@ -907,6 +1031,9 @@ by which they're compared. The iteratee is invoked with one argument: (value).
 
 **Note:** Unlike `differenceBy`, this method mutates `array`.
 
+
+
+
 **Arguments:**
 
 @param array $array The array to modify.
@@ -925,11 +1052,13 @@ Example:
 ```php
 <?php
  use function _\pullAllBy;
+
 $array = [[ 'x' => 1 ], [ 'x' => 2 ], [ 'x' => 3 ], [ 'x' => 1 ]]
 
 pullAllBy($array, [[ 'x' => 1 ], [ 'x' => 3 ]], 'x')
 var_dump($array)
 // => [[ 'x' => 2 ]]
+
 ```
 ### pullAllWith
 
@@ -939,6 +1068,9 @@ invoked with two arguments: (arrVal, othVal).
 
 **Note:** Unlike `differenceWith`, this method mutates `array`.
 
+
+
+
 **Arguments:**
 
 @param array $array The array to modify.
@@ -972,11 +1104,14 @@ array of removed elements.
 
 **Note:** Unlike `at`, this method mutates `array`.
 
+
+
+
 **Arguments:**
 
 @param array $array The array to modify.
 
-@param int|int[] $indexes The indexes of elements to remove.
+@param (int | int[]) $indexes The indexes of elements to remove.
 
 
 
@@ -1008,6 +1143,9 @@ with three arguments: (value, index, array).
 **Note:** Unlike `filter`, this method mutates `array`. Use `pull`
 to pull elements from an array by value.
 
+
+
+
 **Arguments:**
 
 @param array $array The array to modify.
@@ -1024,6 +1162,7 @@ Example:
 ```php
 <?php
  use function _\remove;
+
 $array = [1, 2, 3, 4]
 $evens = remove($array, function ($n) { return $n % 2 === 0; })
 
@@ -1032,247 +1171,2412 @@ var_dump($array)
 
 var_dump($evens)
 // => [2, 4]
+
 ```
-### slice
+### sample
 
-Creates a slice of `array` from `start` up to, but not including, `end`.
+Gets a random element from `array`.
 
 
 
-**Arguments:**
 
-@param array $array The array to slice.
 
-@param int $start The start position.
+**Arguments:**
 
-@param int $end The end position.
+@param array $array The array to sample.
 
 
 
 **Return:**
 
-@return array the slice of `array`.
+@return mixed Returns the random element.
 
-## Collection
+Example:
+```php
+<?php
+ use function _\sample;
 
-### each
+sample([1, 2, 3, 4])
+// => 2
+
+```
+### sampleSize
+
+Gets `n` random elements at unique keys from `array` up to the
+size of `array`.
 
-Iterates over elements of `collection` and invokes `iteratee` for each element.
 
-The iteratee is invoked with three arguments: (value, index|key, collection).
-Iteratee functions may exit iteration early by explicitly returning `false`.
 
-**Note:** As with other "Collections" methods, objects with a "length"
-property are iterated like arrays. To avoid this behavior use `forIn`
-or `forOwn` for object iteration.
 
 **Arguments:**
 
-@param array|object $collection The collection to iterate over.
+@param array $array The array to sample.
 
-@param callable $iteratee The function invoked per iteration.
+@param int $n The number of elements to sample.
 
 
 
 **Return:**
 
-@return array|object Returns `collection`.
+@return array the random elements.
 
 Example:
 ```php
 <?php
- use function _\each;
+ use function _\sampleSize;
 
-each([1, 2], function ($value) { echo $value; })
-// => Echoes `1` then `2`.
+sampleSize([1, 2, 3], 2)
+// => [3, 1]
 
-each((object) ['a' => 1, 'b' => 2], function ($value, $key) { echo $key; });
-// => Echoes 'a' then 'b' (iteration order is not guaranteed).
+sampleSize([1, 2, 3], 4)
+// => [2, 3, 1]
 
 ```
-### map
+### shuffle
 
-Creates an array of values by running each element in `collection` through
-`iteratee`. The iteratee is invoked with three arguments:
-(value, index|key, collection).
+Creates an array of shuffled values
 
-Many lodash-php methods are guarded to work as iteratees for methods like
-`_::every`, `_::filter`, `_::map`, `_::mapValues`, `_::reject`, and `_::some`.
 
-The guarded methods are:
-`ary`, `chunk`, `curry`, `curryRight`, `drop`, `dropRight`, `every`,
-`fill`, `invert`, `parseInt`, `random`, `range`, `rangeRight`, `repeat`,
-`sampleSize`, `slice`, `some`, `sortBy`, `split`, `take`, `takeRight`,
-`template`, `trim`, `trimEnd`, `trimStart`, and `words`
 
-**Arguments:**
 
-@param array|object $collection The collection to iterate over.
+**Arguments:**
 
-@param callable|string|array $iteratee The function invoked per iteration.
+@param array $array The array to shuffle.
 
 
 
 **Return:**
 
-@return array Returns the new mapped array.
+@return array the new shuffled array.
 
 Example:
 ```php
 <?php
- use function _\map;
+ use function _\shuffle;
 
-function square(int $n) {
-  return $n * $n;
-}
+shuffle([1, 2, 3, 4])
+// => [4, 1, 3, 2]
 
-map([4, 8], $square);
-// => [16, 64]
+```
+### slice
 
-map((object) ['a' => 4, 'b' => 8], $square);
-// => [16, 64] (iteration order is not guaranteed)
+Creates a slice of `array` from `start` up to, but not including, `end`.
 
-$users = [
-  [ 'user' => 'barney' ],
-  [ 'user' => 'fred' ]
-];
 
-// The `property` iteratee shorthand.
-map($users, 'user');
-// => ['barney', 'fred']
+
+**Arguments:**
+
+@param array $array The array to slice.
+
+@param int $start The start position.
+
+@param int $end The end position.
+
+
+
+**Return:**
+
+@return array the slice of `array`.
+
+### tail
+
+Gets all but the first element of `array`.
+
+
+
+
+
+**Arguments:**
+
+@param array $array The array to query.
+
+
+
+**Return:**
+
+@return array the slice of `array`.
+
+Example:
+```php
+<?php
+ use function _\tail;
+
+tail([1, 2, 3])
+// => [2, 3]
 
 ```
-### sortBy
+### take
+
+Creates a slice of `array` with `n` elements taken from the beginning.
 
-Creates an array of elements, sorted in ascending order by the results of
-running each element in a collection through each iteratee. This method
-performs a stable sort, that is, it preserves the original sort order of
-equal elements. The iteratees are invoked with one argument: (value).
 
 
 
 **Arguments:**
 
-@param array|object $collection The collection to iterate over.
+@param array $array The array to query.
 
-@param callable|callable[] $iteratees The iteratees to sort by.
+@param int $n The number of elements to take.
 
 
 
 **Return:**
 
-@return array Returns the new sorted array.
+@return array the slice of `array`.
 
 Example:
 ```php
 <?php
- use function _\sortBy;
+ use function _\take;
 
-$users = [
-  [ 'user' => 'fred',   'age' => 48 ],
-  [ 'user' => 'barney', 'age' => 36 ],
-  [ 'user' => 'fred',   'age' => 40 ],
-  [ 'user' => 'barney', 'age' => 34 ],
-];
+take([1, 2, 3])
+// => [1]
 
-sortBy($users, [function($o) { return $o['user']; }]);
-// => [['user' => 'barney', 'age' => 36], ['user' => 'barney', 'age' => 34], ['user' => 'fred', 'age' => 48], ['user' => 'fred', 'age' => 40]]
+take([1, 2, 3], 2)
+// => [1, 2]
 
-sortBy($users, ['user', 'age']);
-// => [['user' => 'barney', 'age' => 34], ['user' => 'barney', 'age' => 36], ['user' => 'fred', 'age' => 40], ['user' => 'fred', 'age' => 48]]
+take([1, 2, 3], 5)
+// => [1, 2, 3]
+
+take([1, 2, 3], 0)
+// => []
 
 ```
-## Date
+### takeRight
 
-### now
+Creates a slice of `array` with `n` elements taken from the end.
 
-Gets the timestamp of the number of milliseconds that have elapsed since the Unix epoch (1 January 1970 00:00:00 UTC).
 
 
 
 **Arguments:**
 
+@param array $array The array to query.
+
+@param int $n The number of elements to take.
+
 
 
 **Return:**
 
-@return int Returns the timestamp.
+@return array the slice of `array`.
+
+Example:
+```php
+<?php
+ use function _\takeRight;
+
+takeRight([1, 2, 3])
+// => [3]
+
+takeRight([1, 2, 3], 2)
+// => [2, 3]
+
+takeRight([1, 2, 3], 5)
+// => [1, 2, 3]
+
+takeRight([1, 2, 3], 0)
+// => []
+
+```
+### takeRightWhile
+
+Creates a slice of `array` with elements taken from the end. Elements are
+taken until `predicate` returns falsey. The predicate is invoked with
+three arguments: (value, index, array).
+
+
+
+
+
+**Arguments:**
+
+@param array $array The array to query.
+
+@param callable $predicate The function invoked per iteration.
+
+
+
+**Return:**
+
+@return array the slice of `array`.
+
+Example:
+```php
+<?php
+ use function _\takeRightWhile;
+
+$users = [
+[ 'user' => 'barney',  'active' => false ],
+[ 'user' => 'fred',    'active' => true ],
+[ 'user' => 'pebbles', 'active' => true ]
+];
+
+takeRightWhile($users, function($value) { return $value['active']; })
+// => objects for ['fred', 'pebbles']
+
+```
+### takeWhile
+
+Creates a slice of `array` with elements taken from the beginning. Elements
+are taken until `predicate` returns falsey. The predicate is invoked with
+three arguments: (value, index, array).
+
+
+
+
+
+**Arguments:**
+
+@param array $array The array to query.
+
+@param mixed $predicate The function invoked per iteration.
+
+
+
+**Return:**
+
+@return array the slice of `array`.
+
+Example:
+```php
+<?php
+ use function _\takeWhile;
+
+$users = [
+[ 'user' => 'barney',  'active' => true ],
+[ 'user' => 'fred',    'active' => true ],
+[ 'user' => 'pebbles', 'active' => false ]
+]
+
+takeWhile($users, function($value) { return $value['active']; })
+// => objects for ['barney', 'fred']
+
+```
+### union
+
+Creates an array of unique values, in order, from all given arrays using
+[`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+for equality comparisons.
+
+
+
+
+
+**Arguments:**
+
+@param array ...$arrays The arrays to inspect.
+
+
+
+**Return:**
+
+@return array the new array of combined values.
+
+Example:
+```php
+<?php
+ use function _\union;
+
+union([2], [1, 2])
+// => [2, 1]
+
+```
+### unionBy
+
+This method is like `union` except that it accepts `iteratee` which is
+invoked for each element of each `arrays` to generate the criterion by
+which uniqueness is computed. Result values are chosen from the first
+array in which the value occurs. The iteratee is invoked with one argument:
+(value).
+
+
+
+
+
+**Arguments:**
+
+@param array<int, mixed> ...$arrays The arrays to inspect.
+
+@param callable $iteratee The iteratee invoked per element.
+
+
+
+**Return:**
+
+@return array the new array of combined values.
+
+Example:
+```php
+<?php
+ use function _\unionBy;
+
+unionBy([2.1], [1.2, 2.3], 'floor')
+// => [2.1, 1.2]
+
+// The `_::property` iteratee shorthand.
+unionBy([['x' => 1]], [['x' => 2], ['x' => 1]], 'x');
+// => [['x' => 1], ['x' => 2]]
+
+```
+### unionWith
+
+This method is like `union` except that it accepts `comparator` which
+is invoked to compare elements of `arrays`. Result values are chosen from
+the first array in which the value occurs. The comparator is invoked
+with two arguments: (arrVal, othVal).
+
+
+
+
+
+
+**Arguments:**
+
+@param array<int, mixed> ...$arrays The arrays to inspect.
+
+@param callable $comparator The comparator invoked per element.
+
+
+
+**Return:**
+
+@return array the new array of combined values.
+
+Example:
+```php
+<?php
+ use function _\unionWith;
+
+$objects = [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1]]
+$others = [['x' => 1, 'y' => 1], ['x' => 1, 'y' => 2]]
+
+unionWith($objects, $others, '_::isEqual')
+// => [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1], ['x' => 1, 'y' => 1]]
+
+```
+### uniq
+
+Creates a duplicate-free version of an array, using
+[`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+for equality comparisons, in which only the first occurrence of each element
+is kept. The order of result values is determined by the order they occur
+in the array.
+
+
+
+
+**Arguments:**
+
+@param array $array The array to inspect.
+
+
+
+**Return:**
+
+@return array the new duplicate free array.
+
+Example:
+```php
+<?php
+ use function _\uniq;
+
+uniq([2, 1, 2])
+// => [2, 1]s
+
+```
+### uniqBy
+
+This method is like `uniq` except that it accepts `iteratee` which is
+invoked for each element in `array` to generate the criterion by which
+uniqueness is computed. The order of result values is determined by the
+order they occur in the array. The iteratee is invoked with one argument:
+(value).
+
+
+
+
+**Arguments:**
+
+@param array $array The array to inspect.
+
+@param mixed $iteratee The iteratee invoked per element.
+
+
+
+**Return:**
+
+@return array the new duplicate free array.
+
+Example:
+```php
+<?php
+ use function _\uniqBy;
+
+uniqBy([2.1, 1.2, 2.3], 'floor')
+// => [2.1, 1.2]
+
+```
+### uniqWith
+
+This method is like `uniq` except that it accepts `comparator` which
+is invoked to compare elements of `array`. The order of result values is
+determined by the order they occur in the array.The comparator is invoked
+with two arguments: (arrVal, othVal).
+
+
+
+
+**Arguments:**
+
+@param array $array The array to inspect.
+
+@param callable $comparator The comparator invoked per element.
+
+
+
+**Return:**
+
+@return array the new duplicate free array.
+
+Example:
+```php
+<?php
+ use function _\uniqWith;
+
+$objects = [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1], ['x' => 1, 'y' => 2]]
+
+uniqWith($objects, '_::isEqual')
+// => [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1]]
+
+```
+### unzip
+
+This method is like `zip` except that it accepts an array of grouped
+elements and creates an array regrouping the elements to their pre-zip
+configuration.
+
+
+
+
+**Arguments:**
+
+@param array $array The array of grouped elements to process.
+
+
+
+**Return:**
+
+@return array the new array of regrouped elements.
+
+Example:
+```php
+<?php
+ use function _\unzip;
+
+$zipped = zip(['a', 'b'], [1, 2], [true, false])
+// => [['a', 1, true], ['b', 2, false]]
+
+unzip($zipped)
+// => [['a', 'b'], [1, 2], [true, false]]
+
+```
+### unzipWith
+
+This method is like `unzip` except that it accepts `iteratee` to specify
+how regrouped values should be combined. The iteratee is invoked with the
+elements of each group: (...group).
+
+
+
+
+
+**Arguments:**
+
+@param array $array The array of grouped elements to process.
+
+@param (callable | null) $iteratee The function to combine regrouped values.
+
+
+
+**Return:**
+
+@return array the new array of regrouped elements.
+
+Example:
+```php
+<?php
+ use function _\unzipWith;
+
+$zipped = zip([1, 2], [10, 20], [100, 200])
+// => [[1, 10, 100], [2, 20, 200]]
+
+unzipWith(zipped, '_::add')
+// => [3, 30, 300]
+
+```
+### without
+
+Creates an array excluding all given values using
+[`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+for equality comparisons.
+
+**Note:** Unlike `pull`, this method returns a new array.
+
+
+
+
+**Arguments:**
+
+@param array $array The array to inspect.
+
+@param array<int, mixed> $values The values to exclude.
+
+
+
+**Return:**
+
+@return array the new array of filtered values.
+
+Example:
+```php
+<?php
+ use function _\without;
+
+without([2, 1, 2, 3], 1, 2)
+// => [3]
+
+```
+### zip
+
+Creates an array of grouped elements, the first of which contains the
+first elements of the given arrays, the second of which contains the
+second elements of the given arrays, and so on.
+
+
+
+
+**Arguments:**
+
+@param array ...$arrays The arrays to process.
+
+
+
+**Return:**
+
+@return array the new array of grouped elements.
+
+Example:
+```php
+<?php
+ use function _\zip;
+
+zip(['a', 'b'], [1, 2], [true, false])
+// => [['a', 1, true], ['b', 2, false]]
+
+```
+### zipObject
+
+This method is like `fromPairs` except that it accepts two arrays,
+one of property identifiers and one of corresponding values.
+
+
+
+
+
+**Arguments:**
+
+@param array $props The property identifiers.
+
+@param array $values The property values.
+
+
+
+**Return:**
+
+@return object the new object.
+
+Example:
+```php
+<?php
+ use function _\zipObject;
+
+zipObject(['a', 'b'], [1, 2])
+/* => object(stdClass)#210 (2) {
+["a"] => int(1)
+["b"] => int(2)
+}
+*\/
+
+```
+### zipObjectDeep
+
+This method is like `zipObject` except that it supports property paths.
+
+
+
+
+
+**Arguments:**
+
+@param array $props The property identifiers.
+
+@param array $values The property values.
+
+
+
+**Return:**
+
+@return \stdClass the new object.
+
+Example:
+```php
+<?php
+ use function _\zipObjectDeep;
+
+zipObjectDeep(['a.b[0].c', 'a.b[1].d'], [1, 2])
+/* => class stdClass#20 (1) {
+public $a => class stdClass#19 (1) {
+public $b =>
+array(2) {
+[0] => class stdClass#17 (1) {
+public $c => int(1)
+}
+[1] => class stdClass#18 (1) {
+public $d => int(2)
+}
+}
+}
+}
+*\/
+
+```
+### zipWith
+
+This method is like `zip` except that it accepts `iteratee` to specify
+how grouped values should be combined. The iteratee is invoked with the
+elements of each group: (...group).
+
+
+
+
+
+**Arguments:**
+
+@param array<int, (array | callable)> ...$arrays The arrays to process.
+
+@param callable $iteratee The function to combine grouped values.
+
+
+
+**Return:**
+
+@return array the new array of grouped elements.
+
+Example:
+```php
+<?php
+ use function _\zipWith;
+
+zipWith([1, 2], [10, 20], [100, 200], function($a, $b, $c) { return $a + $b + $c; })
+// => [111, 222]
+
+```
+## Collection
+
+### countBy
+
+Creates an array composed of keys generated from the results of running
+each element of `collection` through `iteratee`. The corresponding value of
+each key is the number of times the key was returned by `iteratee`. The
+iteratee is invoked with one argument: (value).
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param callable $iteratee The iteratee to transform keys.
+
+
+
+**Return:**
+
+@return array Returns the composed aggregate object.
+
+Example:
+```php
+<?php
+ use function _\countBy;
+
+countBy([6.1, 4.2, 6.3], 'floor');
+// => ['6' => 2, '4' => 1]
+
+// The `property` iteratee shorthand.
+countBy(['one', 'two', 'three'], 'strlen');
+// => ['3' => 2, '5' => 1]
+
+```
+### each
+
+Iterates over elements of `collection` and invokes `iteratee` for each element.
+The iteratee is invoked with three arguments: (value, index|key, collection).
+Iteratee functions may exit iteration early by explicitly returning `false`.
+
+**Note:** As with other "Collections" methods, objects with a "length"
+property are iterated like arrays. To avoid this behavior use `forIn`
+or `forOwn` for object iteration.
+
+
+
+
+
+**Arguments:**
+
+@param (array | iterable | object) $collection The collection to iterate over.
+
+@param callable $iteratee The function invoked per iteration.
+
+
+
+**Return:**
+
+@return (array | object) Returns `collection`.
+
+Example:
+```php
+<?php
+ use function _\each;
+
+each([1, 2], function ($value) { echo $value; })
+// => Echoes `1` then `2`.
+
+each((object) ['a' => 1, 'b' => 2], function ($value, $key) { echo $key; });
+// => Echoes 'a' then 'b' (iteration order is not guaranteed).
+
+```
+### eachRight
+
+This method is like `each` except that it iterates over elements of
+`collection` from right to left.
+
+
+
+
+**Arguments:**
+
+@param (array | iterable | object) $collection The collection to iterate over.
+
+@param callable $iteratee The function invoked per iteration.
+
+
+
+**Return:**
+
+@return (array | object) Returns `collection`.
+
+Example:
+```php
+<?php
+ use function _\eachRight;
+
+eachRight([1, 2], function($value) { echo $value; })
+// => Echoes `2` then `1`.
+
+```
+### filter
+
+Iterates over elements of `array`, returning an array of all elements
+`predicate` returns truthy for. The predicate is invoked with three
+arguments: (value, index, array).
+
+**Note:** Unlike `remove`, this method returns a new array.
+
+
+
+
+
+**Arguments:**
+
+@param iterable $array The array to iterate over.
+
+@param callable $predicate The function invoked per iteration.
+
+
+
+**Return:**
+
+@return array the new filtered array.
+
+Example:
+```php
+<?php
+ use function _\filter;
+
+$users = [
+[ 'user' => 'barney', 'age' => 36, 'active' => true],
+[ 'user' => 'fred',   'age' => 40, 'active' => false]
+];
+
+filter($users, function($o) { return !$o['active']; });
+// => objects for ['fred']
+
+// The `matches` iteratee shorthand.
+filter($users, ['age' => 36, 'active' => true]);
+// => objects for ['barney']
+
+// The `matchesProperty` iteratee shorthand.
+filter($users, ['active', false]);
+// => objects for ['fred']
+
+// The `property` iteratee shorthand.
+filter($users, 'active');
+// => objects for ['barney']
+
+```
+### find
+
+Iterates over elements of `collection`, returning the first element
+`predicate` returns truthy for. The predicate is invoked with three
+arguments: (value, index|key, collection).
+
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to inspect.
+
+@param callable $predicate The function invoked per iteration.
+
+@param int $fromIndex The index to search from.
+
+
+
+**Return:**
+
+@return mixed Returns the matched element, else `null`.
+
+Example:
+```php
+<?php
+ use function _\find;
+
+$users = [
+['user' => 'barney',  'age' => 36, 'active' => true],
+['user' => 'fred',    'age' => 40, 'active' => false],
+['user' => 'pebbles', 'age' => 1,  'active' => true]
+];
+
+find($users, function($o) { return $o['age'] < 40; });
+// => object for 'barney'
+
+// The `matches` iteratee shorthand.
+find($users, ['age' => 1, 'active' => true]);
+// => object for 'pebbles'
+
+// The `matchesProperty` iteratee shorthand.
+find($users, ['active', false]);
+// => object for 'fred'
+
+// The `property` iteratee shorthand.
+find($users, 'active');
+// => object for 'barney'
+
+```
+### findLast
+
+This method is like `find` except that it iterates over elements of
+`collection` from right to left.
+
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to inspect.
+
+@param callable $predicate The function invoked per iteration.
+
+@param int $fromIndex The index to search from.
+
+
+
+**Return:**
+
+@return mixed Returns the matched element, else `undefined`.
+
+Example:
+```php
+<?php
+ use function _\findLast;
+
+findLast([1, 2, 3, 4], function ($n) { return $n % 2 == 1; })
+// => 3
+
+```
+### flatMap
+
+Creates a flattened array of values by running each element in `collection`
+through `iteratee` and flattening the mapped results. The iteratee is invoked
+with three arguments: (value, index|key, collection).
+
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param callable $iteratee The function invoked per iteration.
+
+
+
+**Return:**
+
+@return array the new flattened array.
+
+Example:
+```php
+<?php
+ use function _\flatMap;
+
+function duplicate($n) {
+return [$n, $n]
+}
+
+flatMap([1, 2], 'duplicate')
+// => [1, 1, 2, 2]
+
+```
+### flatMapDeep
+
+This method is like `flatMap` except that it recursively flattens the
+mapped results.
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param callable $iteratee The function invoked per iteration.
+
+
+
+**Return:**
+
+@return array Returns the new flattened array.
+
+Example:
+```php
+<?php
+ use function _\flatMapDeep;
+
+function duplicate($n) {
+return [[[$n, $n]]];
+}
+
+flatMapDeep([1, 2], 'duplicate');
+// => [1, 1, 2, 2]
+
+```
+### flatMapDepth
+
+This method is like `flatMap` except that it recursively flattens the
+mapped results up to `depth` times.
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param callable $iteratee The function invoked per iteration.
+
+@param int $depth The maximum recursion depth.
+
+
+
+**Return:**
+
+@return array the new flattened array.
+
+Example:
+```php
+<?php
+ use function _\flatMapDepth;
+
+function duplicate($n) {
+return [[[$n, $n]]]
+}
+
+flatMapDepth([1, 2], 'duplicate', 2)
+// => [[1, 1], [2, 2]]
+
+```
+### groupBy
+
+Creates an array composed of keys generated from the results of running
+each element of `collection` through `iteratee`. The order of grouped values
+is determined by the order they occur in `collection`. The corresponding
+value of each key is an array of elements responsible for generating the
+key. The iteratee is invoked with one argument: (value).
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param callable $iteratee The iteratee to transform keys.
+
+
+
+**Return:**
+
+@return array Returns the composed aggregate object.
+
+Example:
+```php
+<?php
+ use function _\groupBy;
+
+groupBy([6.1, 4.2, 6.3], 'floor');
+// => ['6' => [6.1, 6.3], '4' => [4.2]]
+
+groupBy(['one', 'two', 'three'], 'strlen');
+// => ['3' => ['one', 'two'], '5' => ['three']]
+
+```
+### invokeMap
+
+Invokes the method at `path` of each element in `collection`, returning
+an array of the results of each invoked method. Any additional arguments
+are provided to each invoked method. If `path` is a function, it's invoked
+for, and `this` bound to, each element in `collection`.
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param (array | callable | string) $path The path of the method to invoke or the function invoked per iteration.
+
+@param array $args The arguments to invoke each method with.
+
+
+
+**Return:**
+
+@return array the array of results.
+
+Example:
+```php
+<?php
+ use function _\invokeMap;
+
+invokeMap([[5, 1, 7], [3, 2, 1]], function($result) { sort($result); return $result;})
+// => [[1, 5, 7], [1, 2, 3]]
+
+invokeMap([123, 456], 'str_split')
+// => [['1', '2', '3'], ['4', '5', '6']]
+
+```
+### keyBy
+
+Creates an object composed of keys generated from the results of running
+each element of `collection` through `iteratee`. The corresponding value of
+each key is the last element responsible for generating the key. The
+iteratee is invoked with one argument: (value).
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param callable $iteratee The iteratee to transform keys.
+
+
+
+**Return:**
+
+@return array the composed aggregate object.
+
+Example:
+```php
+<?php
+ use function _\keyBy;
+
+$array = [
+['direction' => 'left', 'code' => 97],
+['direction' => 'right', 'code' => 100],
+];
+
+keyBy($array, function ($o) { return \chr($o['code']); })
+// => ['a' => ['direction' => 'left', 'code' => 97], 'd' => ['direction' => 'right', 'code' => 100]]
+
+keyBy($array, 'direction');
+// => ['left' => ['direction' => 'left', 'code' => 97], 'right' => ['direction' => 'right', 'code' => 100]]
+
+```
+### map
+
+Creates an array of values by running each element in `collection` through
+`iteratee`. The iteratee is invoked with three arguments:
+(value, index|key, collection).
+
+Many lodash-php methods are guarded to work as iteratees for methods like
+`_::every`, `_::filter`, `_::map`, `_::mapValues`, `_::reject`, and `_::some`.
+
+The guarded methods are:
+`ary`, `chunk`, `curry`, `curryRight`, `drop`, `dropRight`, `every`,
+`fill`, `invert`, `parseInt`, `random`, `range`, `rangeRight`, `repeat`,
+`sampleSize`, `slice`, `some`, `sortBy`, `split`, `take`, `takeRight`,
+`template`, `trim`, `trimEnd`, `trimStart`, and `words`
+
+
+
+
+**Arguments:**
+
+@param (array | object) $collection The collection to iterate over.
+
+@param (callable | string | array) $iteratee The function invoked per iteration.
+
+
+
+**Return:**
+
+@return array Returns the new mapped array.
+
+Example:
+```php
+<?php
+ use function _\map;
+
+function square(int $n) {
+return $n * $n;
+}
+
+map([4, 8], $square);
+// => [16, 64]
+
+map((object) ['a' => 4, 'b' => 8], $square);
+// => [16, 64] (iteration order is not guaranteed)
+
+$users = [
+[ 'user' => 'barney' ],
+[ 'user' => 'fred' ]
+];
+
+// The `property` iteratee shorthand.
+map($users, 'user');
+// => ['barney', 'fred']
+
+```
+### orderBy
+
+This method is like `sortBy` except that it allows specifying the sort
+orders of the iteratees to sort by. If `orders` is unspecified, all values
+are sorted in ascending order. Otherwise, specify an order of "desc" for
+descending or "asc" for ascending sort order of corresponding values.
+
+
+
+
+**Arguments:**
+
+@param (iterable | null) $collection The collection to iterate over.
+
+@param (array[] | callable[] | string[]) $iteratee The iteratee(s) to sort by.
+
+@param string[] $orders The sort orders of `iteratees`.
+
+
+
+**Return:**
+
+@return array the new sorted array.
+
+Example:
+```php
+<?php
+ use function _\orderBy;
+
+$users = [
+['user' => 'fred',   'age' => 48],
+['user' => 'barney', 'age' => 34],
+['user' => 'fred',   'age' => 40],
+['user' => 'barney', 'age' => 36]
+]
+
+// Sort by `user` in ascending order and by `age` in descending order.
+orderBy($users, ['user', 'age'], ['asc', 'desc'])
+// => [['user' => 'barney', 'age' => 36], ['user' => 'barney', 'age' => 34], ['user' => 'fred', 'age' => 48], ['user' => 'fred', 'age' => 40]]
+
+```
+### partition
+
+Creates an array of elements split into two groups, the first of which
+contains elements `predicate` returns truthy for, the second of which
+contains elements `predicate` returns falsey for. The predicate is
+invoked with one argument: (value).
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param callable $predicate The function invoked per iteration.
+
+
+
+**Return:**
+
+@return array the array of grouped elements.
+
+Example:
+```php
+<?php
+ use function _\partition;
+
+$users = [
+['user' => 'barney',  'age' => 36, 'active' => false],
+['user' => 'fred',    'age' => 40, 'active' => true],
+['user' => 'pebbles', 'age' => 1,  'active' => false]
+];
+
+partition($users, function($user) { return $user['active']; })
+// => objects for [['fred'], ['barney', 'pebbles']]
+
+```
+### reduce
+
+Reduces `collection` to a value which is the accumulated result of running
+each element in `collection` thru `iteratee`, where each successive
+invocation is supplied the return value of the previous. If `accumulator`
+is not given, the first element of `collection` is used as the initial
+value. The iteratee is invoked with four arguments:
+(accumulator, value, index|key, collection).
+
+Many lodash methods are guarded to work as iteratees for methods like
+`reduce`, `reduceRight`, and `transform`.
+
+The guarded methods are:
+`assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `orderBy`,
+and `sortBy`
+
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param mixed $iteratee The function invoked per iteration.
+
+@param mixed $accumulator The initial value.
+
+
+
+**Return:**
+
+@return mixed Returns the accumulated value.
+
+Example:
+```php
+<?php
+ use function _\reduce;
+
+reduce([1, 2], function($sum, $n) { return $sum + $n; }, 0)
+// => 3
+
+reduce(['a' => 1, 'b' => 2, 'c' => 1], function ($result, $value, $key) {
+if (!isset($result[$value])) {
+$result[$value] = [];
+}
+$result[$value][] = $key;
+
+return $result;
+}, [])
+// => ['1' => ['a', 'c'], '2' => ['b']] (iteration order is not guaranteed)
+
+```
+### reduceRight
+
+This method is like `reduce` except that it iterates over elements of
+`collection` from right to left.
+
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param mixed $iteratee The function invoked per iteration.
+
+@param mixed $accumulator The initial value.
+
+
+
+**Return:**
+
+@return mixed Returns the accumulated value.
+
+Example:
+```php
+<?php
+ use function _\reduceRight;
+
+$array = [[0, 1], [2, 3], [4, 5]];
+
+reduceRight(array, (flattened, other) => flattened.concat(other), [])
+// => [4, 5, 2, 3, 0, 1]
+
+```
+### reject
+
+The opposite of `filter` this method returns the elements of `collection`
+that `predicate` does **not** return truthy for.
+
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param callable $predicate The function invoked per iteration.
+
+
+
+**Return:**
+
+@return array the new filtered array.
+
+Example:
+```php
+<?php
+ use function _\reject;
+
+$users = [
+['user' => 'barney', 'active' => true],
+['user' => 'fred',   'active' => false]
+]
+
+reject($users, 'active')
+// => objects for ['fred']
+
+```
+### size
+
+Gets the size of `collection` by returning its length for array
+values or the number of public properties for objects.
+
+
+
+
+**Arguments:**
+
+@param (array | object | string) $collection The collection to inspect.
+
+
+
+**Return:**
+
+@return int Returns the collection size.
+
+Example:
+```php
+<?php
+ use function _\size;
+
+size([1, 2, 3]);
+// => 3
+
+size(new class { public $a = 1; public $b = 2; private $c = 3; });
+// => 2
+
+size('pebbles');
+// => 7
+
+```
+### some
+
+Checks if `predicate` returns truthy for **any** element of `collection`.
+Iteration is stopped once `predicate` returns truthy. The predicate is
+invoked with three arguments: (value, index|key, collection).
+
+
+
+
+**Arguments:**
+
+@param iterable $collection The collection to iterate over.
+
+@param (callable | string | array) $predicate The function invoked per iteration.
+
+
+
+**Return:**
+
+@return boolean Returns `true` if any element passes the predicate check, else `false`.
+
+Example:
+```php
+<?php
+ use function _\some;
+
+some([null, 0, 'yes', false], , function ($value) { return \is_bool($value); }));
+// => true
+
+$users = [
+['user' => 'barney', 'active' => true],
+['user' => 'fred',   'active' => false]
+];
+
+// The `matches` iteratee shorthand.
+some($users, ['user' => 'barney', 'active' => false ]);
+// => false
+
+// The `matchesProperty` iteratee shorthand.
+some($users, ['active', false]);
+// => true
+
+// The `property` iteratee shorthand.
+some($users, 'active');
+// => true
+
+```
+### sortBy
+
+Creates an array of elements, sorted in ascending order by the results of
+running each element in a collection through each iteratee. This method
+performs a stable sort, that is, it preserves the original sort order of
+equal elements. The iteratees are invoked with one argument: (value).
+
+
+
+
+**Arguments:**
+
+@param (array | object | null) $collection The collection to iterate over.
+
+@param (callable | callable[]) $iteratees The iteratees to sort by.
+
+
+
+**Return:**
+
+@return array Returns the new sorted array.
+
+Example:
+```php
+<?php
+ use function _\sortBy;
+
+$users = [
+[ 'user' => 'fred',   'age' => 48 ],
+[ 'user' => 'barney', 'age' => 36 ],
+[ 'user' => 'fred',   'age' => 40 ],
+[ 'user' => 'barney', 'age' => 34 ],
+];
+
+sortBy($users, [function($o) { return $o['user']; }]);
+// => [['user' => 'barney', 'age' => 36], ['user' => 'barney', 'age' => 34], ['user' => 'fred', 'age' => 48], ['user' => 'fred', 'age' => 40]]
+
+sortBy($users, ['user', 'age']);
+// => [['user' => 'barney', 'age' => 34], ['user' => 'barney', 'age' => 36], ['user' => 'fred', 'age' => 40], ['user' => 'fred', 'age' => 48]]
+
+```
+## Date
+
+### now
+
+Gets the timestamp of the number of milliseconds that have elapsed since the Unix epoch (1 January 1970 00:00:00 UTC).
+
+
+
+
+**Arguments:**
+
+
+
+**Return:**
+
+@return int Returns the timestamp.
+
+Example:
+```php
+<?php
+ use function _\now;
+
+now();
+// => 1511180325735
+
+```
+## Function
+
+### after
+
+The opposite of `before`; this method creates a function that invokes
+`func` once it's called `n` or more times.
+
+
+
+
+
+**Arguments:**
+
+@param int $n The number of calls before `func` is invoked.
+
+@param Callable $func The function to restrict.
+
+
+
+**Return:**
+
+@return Callable Returns the new restricted function.
+
+Example:
+```php
+<?php
+ use function _\after;
+
+$saves = ['profile', 'settings'];
+
+$done = after(count($saves), function() {
+echo 'done saving!';
+});
+
+forEach($saves, function($type) use($done) {
+asyncSave([ 'type' => $type, 'complete' => $done ]);
+});
+// => Prints 'done saving!' after the two async saves have completed.
+
+```
+### ary
+
+Creates a function that invokes `func`, with up to `n` arguments,
+ignoring any additional arguments.
+
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to cap arguments for.
+
+@param int $n The arity cap.
+
+
+
+**Return:**
+
+@return Callable Returns the new capped function.
+
+Example:
+```php
+<?php
+ use function _\ary;
+
+map(['6', '8', '10'], ary('intval', 1));
+// => [6, 8, 10]
+
+```
+### before
+
+Creates a function that invokes `func`, with the arguments
+of the created function, while it's called less than `n` times. Subsequent
+calls to the created function return the result of the last `func` invocation.
+
+
+
+
+
+**Arguments:**
+
+@param int $n The number of calls at which `func` is no longer invoked.
+
+@param callable $func The function to restrict.
+
+
+
+**Return:**
+
+@return callable Returns the new restricted function.
+
+Example:
+```php
+<?php
+ use function _\before;
+
+$users = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+$result = uniqBy(map($users, before(5, [$repository, 'find'])), 'id')
+// => Fetch up to 4 results.
+
+```
+### bind
+
+Creates a function that invokes `func` with the `this` binding of `object`
+and `partials` prepended to the arguments it receives.
+
+
+
+
+**Arguments:**
+
+@param callable $function The function to bind.
+
+@param (object | mixed) $object The `object` binding of `func`.
+
+@param array<int, mixed> $partials The arguments to be partially applied.
+
+
+
+**Return:**
+
+@return callable Returns the new bound function.
+
+Example:
+```php
+<?php
+ use function _\bind;
+
+function greet($greeting, $punctuation) {
+return $greeting . ' ' . $this->user . $punctuation;
+}
+
+$object = $object = new class {
+public $user = 'fred';
+};
+
+$bound = bind('greet', $object, 'hi');
+$bound('!');
+// => 'hi fred!'
+
+```
+### bindKey
+
+Creates a function that invokes the method `$function` of `$object` with `$partials`
+prepended to the arguments it receives.
+
+This method differs from `bind` by allowing bound functions to reference
+methods that may be redefined or don't yet exist
+
+
+
+
+**Arguments:**
+
+@param object $object The object to invoke the method on.
+
+@param string $function The name of the method.
+
+@param array<int, mixed> $partials The arguments to be partially applied.
+
+
+
+**Return:**
+
+@return callable Returns the new bound function.
+
+Example:
+```php
+<?php
+ use function _\bindKey;
+
+$object = new class {
+private $user = 'fred';
+function greet($greeting, $punctuation) {
+return $greeting.' '.$this->user.$punctuation;
+}
+};
+
+$bound = bindKey($object, 'greet', 'hi');
+$bound('!');
+// => 'hi fred!'
+
+```
+### curry
+
+Creates a function that accepts arguments of `func` and either invokes
+`func` returning its result, if at least `arity` number of arguments have
+been provided, or returns a function that accepts the remaining `func`
+arguments, and so on. The arity of `func` may be specified if `func.length`
+is not sufficient.
+
+The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
+may be used as a placeholder for provided arguments.
+
+**Note:** This method doesn't set the "length" property of curried functions.
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to curry.
+
+@param (int | null) $arity The arity of `func`.
+
+
+
+**Return:**
+
+@return callable Returns the new curried function.
+
+Example:
+```php
+<?php
+ use function _\curry;
+
+$abc = function($a, $b, $c) {
+return [$a, $b, $c];
+};
+
+$curried = curry($abc);
+
+$curried(1)(2)(3);
+// => [1, 2, 3]
+
+$curried(1, 2)(3);
+// => [1, 2, 3]
+
+$curried(1, 2, 3);
+// => [1, 2, 3]
+
+// Curried with placeholders.
+$curried(1)(_, 3)(2);
+// => [1, 2, 3]
+
+```
+### delay
+
+Invokes `func` after `wait` milliseconds. Any additional arguments are
+provided to `func` when it's invoked.
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to delay.
+
+@param int $wait The number of milliseconds to delay invocation.
+
+@param array<int, mixed> $args
+
+
+
+**Return:**
+
+@return int the timer id.
+
+Example:
+```php
+<?php
+ use function _\delay;
+
+delay(function($text) {
+echo $text;
+}, 1000, 'later');
+// => Echo 'later' after one second.
+
+```
+### flip
+
+Creates a function that invokes `func` with arguments reversed.
+
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to flip arguments for.
+
+
+
+**Return:**
+
+@return callable Returns the new flipped function.
+
+Example:
+```php
+<?php
+ use function _\flip;
+
+$flipped = flip(function() {
+return func_get_args();
+});
+
+flipped('a', 'b', 'c', 'd');
+// => ['d', 'c', 'b', 'a']
+
+```
+### memoize
+
+Creates a function that memoizes the result of `func`. If `resolver` is
+provided, it determines the cache key for storing the result based on the
+arguments provided to the memoized function. By default, the first argument
+provided to the memoized function is used as the map cache key
+
+**Note:** The cache is exposed as the `cache` property on the memoized
+function. Its creation may be customized by replacing the `_.memoize.Cache`
+constructor with one whose instances implement the
+[`Map`](http://ecma-international.org/ecma-262/7.0/#sec-properties-of-the-map-prototype-object)
+method interface of `clear`, `delete`, `get`, `has`, and `set`.
+
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to have its output memoized.
+
+@param (callable | null) $resolver The function to resolve the cache key.
+
+
+
+**Return:**
+
+@return callable Returns the new memoized function.
+
+Example:
+```php
+<?php
+ use function _\memoize;
+
+$object = ['a' => 1, 'b' => 2];
+$other = ['c' => 3, 'd' => 4];
+
+$values = memoize('_\values');
+$values($object);
+// => [1, 2]
+
+$values($other);
+// => [3, 4]
+
+$object['a'] = 2;
+$values($object);
+// => [1, 2]
+
+// Modify the result cache.
+$values->cache->set($object, ['a', 'b']);
+$values($object);
+// => ['a', 'b']
+
+```
+### negate
+
+Creates a function that negates the result of the predicate `func`
+
+
+
+
+
+**Arguments:**
+
+@param callable $predicate The predicate to negate.
+
+
+
+**Return:**
+
+@return callable Returns the new negated function.
+
+Example:
+```php
+<?php
+ use function _\negate;
+
+function isEven($n) {
+return $n % 2 == 0;
+}
+
+filter([1, 2, 3, 4, 5, 6], negate($isEven));
+// => [1, 3, 5]
+
+```
+### once
+
+Creates a function that is restricted to invoking `func` once. Repeat calls
+to the function return the value of the first invocation. The `func` is
+invoked with the arguments of the created function.
+
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to restrict.
+
+
+
+**Return:**
+
+@return callable the new restricted function.
+
+Example:
+```php
+<?php
+ use function _\once;
+
+$initialize = once('createApplication');
+$initialize();
+$initialize();
+// => `createApplication` is invoked once
+
+```
+### overArgs
+
+Creates a function that invokes `func` with its arguments transformed.
+
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to wrap.
+
+@param callable[] $transforms The argument transforms.
+
+
+
+**Return:**
+
+@return callable the new function.
+
+Example:
+```php
+<?php
+ use function _\overArgs;
+
+function doubled($n) {
+return $n * 2;
+}
+
+function square($n) {
+return $n * $n;
+}
+
+$func = overArgs(function($x, $y) {
+return [$x, $y];
+}, ['square', 'doubled']);
+
+$func(9, 3);
+// => [81, 6]
+
+$func(10, 5);
+// => [100, 10]
+
+```
+### partial
+
+Creates a function that invokes `func` with `partials` prepended to the
+arguments it receives.
+
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to partially apply arguments to.
+
+@param array<int, mixed> $partials The arguments to be partially applied.
+
+
+
+**Return:**
+
+@return callable Returns the new partially applied function.
+
+Example:
+```php
+<?php
+ use function _\partial;
+
+function greet($greeting, $name) {
+return $greeting . ' ' . $name;
+}
+
+$sayHelloTo = partial('greet', 'hello');
+$sayHelloTo('fred');
+// => 'hello fred'
+
+```
+### rest
+
+Creates a function that invokes `func` with the `this` binding of the
+created function and arguments from `start` and beyond provided as
+an array.
+
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to apply a rest parameter to.
+
+@param (int | null) $start The start position of the rest parameter.
+
+
+
+**Return:**
+
+@return callable Returns the new function.
+
+Example:
+```php
+<?php
+ use function _\rest;
+
+$say = rest(function($what, $names) {
+return $what . ' ' . implode(', ', initial($names)) .
+(size($names) > 1 ? ', & ' : '') . last($names);
+});
+
+$say('hello', 'fred', 'barney', 'pebbles');
+// => 'hello fred, barney, & pebbles'
+
+```
+### spread
+
+Creates a function that invokes `func` with the `this` binding of the
+create function and an array of arguments much like
+[`Function#apply`](http://www.ecma-international.org/ecma-262/7.0/#sec-function.prototype.apply).
+
+**Note:** This method is based on the
+[spread operator](https://mdn.io/spread_operator).
+
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to spread arguments over.
+
+@param int $start The start position of the spread.
+
+
+
+**Return:**
+
+@return callable Returns the new function.
+
+Example:
+```php
+<?php
+ use function _\spread;
+
+$say = spread(function($who, $what) {
+return $who . ' says ' . $what;
+});
+
+$say(['fred', 'hello']);
+// => 'fred says hello'
+
+```
+### unary
+
+Creates a function that accepts up to one argument, ignoring any
+additional arguments.
+
+
+
+
+**Arguments:**
+
+@param callable $func The function to cap arguments for.
+
+
+
+**Return:**
+
+@return callable the new capped function.
+
+Example:
+```php
+<?php
+ use function _\unary;
+
+map(['6', '8', '10'], unary('intval'));
+// => [6, 8, 10]
+
+```
+### wrap
+
+Creates a function that provides `value` to `wrapper` as its first
+argument. Any additional arguments provided to the function are appended
+to those provided to the `wrapper`.
+
+
+
+
+**Arguments:**
+
+@param mixed $value The value to wrap.
+
+@param callable $wrapper The wrapper function.
+
+
+
+**Return:**
+
+@return callable the new function.
+
+Example:
+```php
+<?php
+ use function _\wrap;
+
+$p = wrap('_\escape', function($func, $text) {
+return '<p>' . $func($text) . '</p>';
+});
+
+$p('fred, barney, & pebbles');
+// => '<p>fred, barney, &amp; pebbles</p>'
+
+```
+## Lang
+
+### eq
+
+Performs a comparison between two values to determine if they are equivalent.
+
+
+
+
+**Arguments:**
+
+@param mixed $value The value to compare.
+
+@param mixed $other The other value to compare.
+
+
+
+**Return:**
+
+@return boolean Returns `true` if the values are equivalent, else `false`.
+
+Example:
+```php
+<?php
+ use function _\eq;
+
+$object = (object) ['a' => 1];
+$other = (object) ['a' => 1];
+
+eq($object, $object);
+// => true
+
+eq($object, $other);
+// => false
+
+eq('a', 'a');
+// => true
+
+eq(['a'], (object) ['a']);
+// => false
+
+eq(INF, INF);
+// => true
+
+```
+### isEqual
+
+Performs a deep comparison between two values to determine if they are
+equivalent.
+
+**Note:** This method supports comparing arrays, booleans,
+DateTime objects, exception objects, SPLObjectStorage, numbers,
+strings, typed arrays, resources, DOM Nodes. objects are compared
+by their own, not inherited, enumerable properties.
+
+
+
+
+
+**Arguments:**
+
+@param mixed $value The value to compare.
+
+@param mixed $other The other value to compare.
+
+
+
+**Return:**
+
+@return bool Returns `true` if the values are equivalent, else `false`.
+
+Example:
+```php
+<?php
+ use function _\isEqual;
+
+
+$object = [ 'a' => 1]
+$other = ['a' => '1']
+
+isEqual($object, $other)
+// => true
+
+$object === $other
+// => false
+
+```
+### isError
+
+Checks if `value` is an `\Exception`, `\ParseError`, \Error`, \Throwable`, \SoapFault`, \DOMException`, \PDOException`, object.
+
+
+
+
+
+**Arguments:**
+
+@param mixed $value The value to check.
+
+
+
+**Return:**
+
+@return boolean Returns `true` if `value` is an error object, else `false`.
+
+Example:
+```php
+<?php
+ use function _\isError;
+
+isError(new \Exception())
+// => true
+
+isError(\Exception::Class)
+// => false
+
+```
+## Math
+
+### add
+
+Adds two numbers.
+
+
+
+
+
+**Arguments:**
+
+@param (int | float | string) $augend The first number in an addition.
+
+@param (int | float | string) $addend The second number in an addition.
+
+
+
+**Return:**
+
+@return (int | float) Returns the total.
 
 Example:
 ```php
 <?php
- use function _\now;
+ use function _\add;
 
-now();
-// => 1511180325735
+add(6, 4);
+// => 10
 
 ```
-## Lang
+### max
 
-### isEqual
+Computes the maximum value of `array`. If `array` is empty or falsey, null is returned.
 
-Performs a deep comparison between two values to determine if they are
-equivalent.
 
-**Note:** This method supports comparing arrays, booleans,
-DateTime objects, exception objects, SPLObjectStorage, numbers,
-strings, typed arrays, resources, DOM Nodes. objects are compared
-by their own, not inherited, enumerable properties.
 
-**Arguments:**
 
-@param mixed $value The value to compare.
+**Arguments:**
 
-@param mixed $other The other value to compare.
+@param (array | null) $array The array to iterate over.
 
 
 
 **Return:**
 
-@return bool Returns `true` if the values are equivalent, else `false`.
+@return (int | null) Returns the maximum value.
 
 Example:
 ```php
 <?php
- use function _\isEqual;
-
-
-$object = [ 'a' => 1]
-$other = ['a' => '1']
+ use function _\max;
 
-isEqual($object, $other)
-// => true
+max([4, 2, 8, 6]);
+// => 8
 
-$object === $other
-// => false
+max([]);
+// => null
 
 ```
-### isError
+### maxBy
+
+This method is like `max` except that it accepts `iteratee` which is
+invoked for each element in `array` to generate the criterion by which
+the value is ranked. The iteratee is invoked with one argument: (value).
 
-Checks if `value` is an `\Exception`, `\ParseError`, \Error`, \Throwable`, \SoapFault`, \DOMException`, \PDOException`, object.
 
 
 
 **Arguments:**
 
-@param mixed $value The value to check.
+@param array $array The array to iterate over.
+
+@param (callable | string) $iteratee The iteratee invoked per element.
 
 
 
 **Return:**
 
-@return bool Returns `true` if `value` is an error object, else `false`.
+@return mixed Returns the maximum value.
 
 Example:
 ```php
 <?php
- use function _\isError;
+ use function _\maxBy;
 
-isError(new \Exception())
-// => true
+$objects = [['n' => 1], ['n' => 2]];
+
+maxBy($objects, function($o) { return $o['n']; });
+// => ['n' => 2]
+
+// The `property` iteratee shorthand.
+maxBy($objects, 'n');
+// => ['n' => 2]
 
-isError(\Exception::Class)
-// => false
 ```
 ## Number
 
@@ -1282,13 +3586,15 @@ Clamps `number` within the inclusive `lower` and `upper` bounds.
 
 
 
+
+
 **Arguments:**
 
-@param int $ number The number to clamp.
+@param int $number The number to clamp.
 
-@param int $ lower The lower bound.
+@param int $lower The lower bound.
 
-@param int $ upper The upper bound.
+@param int $upper The upper bound.
 
 
 
@@ -1312,13 +3618,16 @@ clamp(10, -5, 5)
 
 Checks if `number` is between `start` and up to, but not including, `end`. If
 `end` is not specified, it's set to `start` with `start` then set to `0`.
-
 If `start` is greater than `end` the params are swapped to support
 negative ranges.
 
+
+
+
+
 **Arguments:**
 
-@param float $ number The number to check.
+@param float $number The number to check.
 
 @param float $start The start of the range.
 
@@ -1328,7 +3637,7 @@ negative ranges.
 
 **Return:**
 
-@return bool Returns `true` if `number` is in the range, else `false`.
+@return boolean Returns `true` if `number` is in the range, else `false`.
 
 Example:
 ```php
@@ -1360,29 +3669,33 @@ inRange(-3, -2, -6)
 ### random
 
 Produces a random number between the inclusive `lower` and `upper` bounds.
-
 If only one argument is provided a number between `0` and the given number
 is returned. If `floating` is `true`, or either `lower` or `upper` are
 floats, a floating-point number is returned instead of an integer.
 
+
+
+
+
 **Arguments:**
 
-@param int|float $lower The lower bound.
+@param (int | float | bool) $lower The lower bound.
 
-@param int|float $upper The upper bound.
+@param (int | float | bool) $upper The upper bound.
 
-@param bool $floating Specify returning a floating-point number.
+@param (bool | null) $floating Specify returning a floating-point number.
 
 
 
 **Return:**
 
-@return int|float Returns the random number.
+@return (int | float) Returns the random number.
 
 Example:
 ```php
 <?php
  use function _\random;
+
 random(0, 5)
 // => an integer between 0 and 5
 
@@ -1394,6 +3707,151 @@ random(5, true)
 
 random(1.2, 5.2)
 // => a floating-point number between 1.2 and 5.2
+
+```
+## Object
+
+### get
+
+Gets the value at path of object. If the resolved value is null the defaultValue is returned in its place.
+
+
+
+
+
+
+**Arguments:**
+
+@param mixed $object The associative array or object to fetch value from
+
+@param (array | string) $path Dot separated or array of string
+
+@param mixed $defaultValue (optional)The value returned for unresolved or null values.
+
+
+
+**Return:**
+
+@return mixed Returns the resolved value.
+
+Example:
+```php
+<?php
+ use function _\get;
+
+$sampleArray = ["key1" => ["key2" => ["key3" => "val1", "key4" => ""]]];
+get($sampleArray, 'key1.key2.key3');
+// => "val1"
+
+get($sampleArray, 'key1.key2.key5', "default");
+// => "default"
+
+get($sampleArray, 'key1.key2.key4', "default");
+// => ""
+
+```
+### pick
+
+Creates an object composed of the picked `object` properties.
+
+
+
+
+**Arguments:**
+
+@param object $object The source object.
+
+@param (string | string[]) $paths The property paths to pick.
+
+
+
+**Return:**
+
+@return \stdClass Returns the new object.
+
+Example:
+```php
+<?php
+ use function _\pick;
+
+$object = (object) ['a' => 1, 'b' => '2', 'c' => 3];
+
+pick($object, ['a', 'c']);
+// => (object) ['a' => 1, 'c' => 3]
+
+```
+### pickBy
+
+Creates an object composed of the `object` properties `predicate` returns
+truthy for. The predicate is invoked with two arguments: (value, key).
+
+
+
+
+**Arguments:**
+
+@param (object | null) $object The source object.
+
+@param callable $predicate The function invoked per property.
+
+
+
+**Return:**
+
+@return \stdClass Returns the new object.
+
+Example:
+```php
+<?php
+ use function _\pickBy;
+
+$object = (object) ['a' => 1, 'b' => 'abc', 'c' => 3];
+
+pickBy(object, 'is_numeric');
+// => (object) ['a' => 1, 'c' => 3]
+
+```
+## Seq
+
+### chain
+
+Creates a `lodash` wrapper instance that wraps `value` with explicit method
+chain sequences enabled. The result of such sequences must be unwrapped
+with `->value()`.
+
+
+
+
+**Arguments:**
+
+@param mixed $value The value to wrap.
+
+
+
+**Return:**
+
+@return \_ Returns the new `lodash` wrapper instance.
+
+Example:
+```php
+<?php
+ use function _\chain;
+
+$users = [
+['user' => 'barney',  'age' => 36],
+['user' => 'fred',    'age' => 40],
+['user' => 'pebbles', 'age' => 1 ],
+];
+
+$youngest = chain($users)
+->sortBy('age')
+->map(function($o) {
+return $o['user'] . ' is ' . $o['age'];
+})
+->head()
+->value();
+// => 'pebbles is 1'
+
 ```
 ## String
 
@@ -1403,6 +3861,8 @@ Converts `string` to [camel case](https://en.wikipedia.org/wiki/CamelCase).
 
 
 
+
+
 **Arguments:**
 
 @param string $string The string to convert.
@@ -1435,6 +3895,7 @@ to lower case.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to capitalize.
@@ -1464,6 +3925,8 @@ letters to basic Latin letters and removing
 
 
 
+
+
 **Arguments:**
 
 @param string $string The string to deburr.
@@ -1478,8 +3941,10 @@ Example:
 ```php
 <?php
  use function _\deburr;
+
 deburr('déjà vu')
 // => 'deja vu'
+
 ```
 ### endsWith
 
@@ -1487,6 +3952,7 @@ Checks if `string` ends with the given target string.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to inspect.
@@ -1499,7 +3965,7 @@ Checks if `string` ends with the given target string.
 
 **Return:**
 
-@return bool Returns `true` if `string` ends with `target`, else `false`.
+@return boolean Returns `true` if `string` ends with `target`, else `false`.
 
 Example:
 ```php
@@ -1521,6 +3987,7 @@ endsWith('abc', 'b', 2)
 Converts the characters "&", "<", ">", '"', and "'" in `string` to their
 corresponding HTML entities.
 
+
 Though the ">" character is escaped for symmetry, characters like
 ">" and "/" don't need escaping in HTML and have no special meaning
 unless they're part of a tag or unquoted attribute value. See
@@ -1531,6 +3998,9 @@ When working with HTML you should always
 [quote attribute values](http://wonko.com/post/html-escaping) to reduce
 XSS vectors.
 
+
+
+
 **Arguments:**
 
 @param string $string The string to escape.
@@ -1557,6 +4027,7 @@ Escapes the `RegExp` special characters "^", "$", "\", ".", "*", "+",
 
 
 
+
 **Arguments:**
 
 @param string $string The string to escape.
@@ -1583,6 +4054,7 @@ Converts `string` to
 
 
 
+
 **Arguments:**
 
 @param string $string The string to convert.
@@ -1614,6 +4086,7 @@ Converts `string`, as space separated words, to lower case.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to convert.
@@ -1645,6 +4118,7 @@ Converts the first character of `string` to lower case.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to convert.
@@ -1670,9 +4144,12 @@ lowerFirst('FRED')
 ### pad
 
 Pads `string` on the left and right sides if it's shorter than `length`.
-
 Padding characters are truncated if they can't be evenly divided by `length`.
 
+
+
+
+
 **Arguments:**
 
 @param string $string The string to pad.
@@ -1709,6 +4186,8 @@ characters are truncated if they exceed `length`.
 
 
 
+
+
 **Arguments:**
 
 @param string $string The string to pad.
@@ -1745,6 +4224,7 @@ characters are truncated if they exceed `length`.
 
 
 
+s
 **Arguments:**
 
 @param string $string ='' The string to pad.
@@ -1772,7 +4252,7 @@ padStart('abc', 6, '_-')
 
 padStart('abc', 2)
 // => 'abc'
-s
+
 ```
 ### parseInt
 
@@ -1783,9 +4263,13 @@ hexadecimal, in which case a `radix` of `16` is used.
 **Note:** This method uses PHP's built-in integer casting, which does not necessarily align with the
 [ES5 implementation](https://es5.github.io/#x15.1.2.2) of `parseInt`.
 
+
+
+
+
 **Arguments:**
 
-@param int|float|string $string The string to convert.
+@param (int | float | string) $string The string to convert.
 
 @param int $radix The radix to interpret `string` by.
 
@@ -1810,6 +4294,8 @@ Repeats the given string `n` times.
 
 
 
+
+
 **Arguments:**
 
 @param string $string The string to repeat.
@@ -1844,13 +4330,17 @@ Replaces matches for `pattern` in `string` with `replacement`.
 **Note:** This method is based on
 [`String#replace`](https://mdn.io/String/replace).
 
+
+
+
+
 **Arguments:**
 
 @param string $string The string to modify.
 
 @param string $pattern The pattern to replace.
 
-@param callable|string $ replacement The match replacement.
+@param (callable | string) $replacement The match replacement.
 
 
 
@@ -1873,7 +4363,6 @@ Converts `string` to
 [snake case](https://en.wikipedia.org/wiki/Snake_case).
 
 
-
 **Arguments:**
 
 @param string $string The string to convert.
@@ -1888,6 +4377,7 @@ Example:
 ```php
 <?php
  use function _\snakeCase;
+
 snakeCase('Foo Bar')
 // => 'foo_bar'
 
@@ -1896,6 +4386,7 @@ snakeCase('fooBar')
 
 snakeCase('--FOO-BAR--')
 // => 'foo_bar'
+
 ```
 ### split
 
@@ -1904,9 +4395,12 @@ Splits `string` by `separator`.
 **Note:** This method is based on
 [`String#split`](https://mdn.io/String/split).
 
+
+
+
 **Arguments:**
 
-@param string $ string The string to split.
+@param string $string The string to split.
 
 @param string $separator The separator pattern to split by.
 
@@ -1934,6 +4428,7 @@ Converts `string` to
 
 
 
+
 **Arguments:**
 
 @param string $string The string to convert.
@@ -1965,6 +4460,7 @@ Checks if `string` starts with the given target string.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to inspect.
@@ -1977,7 +4473,7 @@ Checks if `string` starts with the given target string.
 
 **Return:**
 
-@return bool Returns `true` if `string` starts with `target`, else `false`.
+@return boolean Returns `true` if `string` starts with `target`, else `false`.
 
 Example:
 ```php
@@ -2003,16 +4499,18 @@ properties may be accessed as free variables in the template. If a setting
 object is given, it takes precedence over `$templateSettings` values.
 
 
+RegExp $options['escape'] = _::$templateSettings['escape'] The HTML "escape" delimiter.
+RegExp $options['evaluate'] = _::$templateSettings['evaluate'] The "evaluate" delimiter.
+array  $options['imports'] = _::$templateSettings['imports'] An object to import into the template as free variables.
+RegExp $options['interpolate'] = _::$templateSettings['interpolate'] The "interpolate" delimiter.
+
+
 
 **Arguments:**
 
 @param string $string The template string.
 
 @param array $options The options array.
-RegExp $options['escape'] = _::$templateSettings['escape'] The HTML "escape" delimiter.
-RegExp $options['evaluate'] = _::$templateSettings['evaluate'] The "evaluate" delimiter.
-array  $options['imports'] = _::$templateSettings['imports'] An object to import into the template as free variables.
-RegExp $options['interpolate'] = _::$templateSettings['interpolate'] The "interpolate" delimiter.
 
 
 
@@ -2072,6 +4570,7 @@ Converts `string`, as a whole, to lower case
 
 
 
+
 **Arguments:**
 
 @param string $string The string to convert.
@@ -2103,6 +4602,7 @@ Converts `string`, as a whole, to upper case
 
 
 
+
 **Arguments:**
 
 @param string $string The string to convert.
@@ -2126,6 +4626,7 @@ toUpper('fooBar')
 
 toUpper('__foo_bar__')
 // => '__FOO_BAR__'
+
 ```
 ### trim
 
@@ -2133,6 +4634,7 @@ Removes leading and trailing whitespace or specified characters from `string`.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to trim.
@@ -2163,6 +4665,7 @@ Removes trailing whitespace or specified characters from `string`.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to trim.
@@ -2179,11 +4682,13 @@ Example:
 ```php
 <?php
  use function _\trimEnd;
+
 trimEnd('  abc  ')
 // => '  abc'
 
 trimEnd('-_-abc-_-', '_-')
 // => '-_-abc'
+
 ```
 ### trimStart
 
@@ -2191,6 +4696,7 @@ Removes leading whitespace or specified characters from `string`.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to trim.
@@ -2218,18 +4724,21 @@ trimStart('-_-abc-_-', '_-')
 ### truncate
 
 Truncates `string` if it's longer than the given maximum string length.
-
 The last characters of the truncated string are replaced with the omission
 string which defaults to "...".
 
+
+length = 30 The maximum string length.
+omission = '...' The string to indicate text is omitted.
+separator The separator pattern to truncate to.
+
+
+
 **Arguments:**
 
 @param string $string The string to truncate.
 
 @param array $options The options object.
-length = 30 The maximum string length.
-omission = '...' The string to indicate text is omitted.
-separator The separator pattern to truncate to.
 
 
 
@@ -2246,19 +4755,19 @@ truncate('hi-diddly-ho there, neighborino')
 // => 'hi-diddly-ho there, neighbo...'
 
 truncate('hi-diddly-ho there, neighborino', [
-  'length' => 24,
-  'separator' => ' '
+'length' => 24,
+'separator' => ' '
 ])
 // => 'hi-diddly-ho there,...'
 
 truncate('hi-diddly-ho there, neighborino', [
-  'length' => 24,
-  'separator' => '/,? +/'
+'length' => 24,
+'separator' => '/,? +/'
 ])
 // => 'hi-diddly-ho there...'
 
 truncate('hi-diddly-ho there, neighborino', [
-  'omission' => ' [...]'
+'omission' => ' [...]'
 ])
 // => 'hi-diddly-ho there, neig [...]'
 
@@ -2271,6 +4780,7 @@ their corresponding characters.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to unescape.
@@ -2295,7 +4805,6 @@ unescape('fred, barney, &amp; pebbles')
 Converts `string`, as space separated words, to upper case.
 
 
-
 **Arguments:**
 
 @param string $string The string to convert.
@@ -2327,6 +4836,7 @@ Converts the first character of `string` to upper case.
 
 
 
+
 **Arguments:**
 
 @param string $string The string to convert.
@@ -2355,6 +4865,8 @@ Splits `string` into an array of its words.
 
 
 
+
+
 **Arguments:**
 
 @param string $string The string to inspect.
@@ -2388,17 +4900,19 @@ object. Any additional arguments are provided to `func` when it's invoked.
 
 
 
+
+s
 **Arguments:**
 
 @param callable $func The function to attempt.
 
-@param array $args The arguments to invoke `func` with.
+@param array<int, mixed> $args The arguments to invoke `func` with.
 
 
 
 **Return:**
 
-@return mixed|\Throwable Returns the `func` result or error object.
+@return (mixed | \Throwable) Returns the `func` result or error object.
 
 Example:
 ```php
@@ -2407,13 +4921,51 @@ Example:
 
 // Avoid throwing errors for invalid PDO data source.
 $elements = attempt(function () {
-   new \PDO(null);
+new \PDO(null);
 });
 
 if (isError($elements)) {
-  $elements = [];
+$elements = [];
 }
-s
+
+```
+### defaultTo
+
+Checks value to determine whether a default value should be returned in its place.
+The defaultValue is returned if value is NaN or null.
+
+
+
+
+
+
+**Arguments:**
+
+@param mixed $value Any value.
+
+@param mixed $defaultValue Value to return when $value is null or NAN
+
+
+
+**Return:**
+
+@return mixed Returns `value`.
+
+Example:
+```php
+<?php
+ use function _\defaultTo;
+
+$a = null;
+
+defaultTo($a, "default");
+// => "default"
+
+$a = "x";
+
+defaultTo($a, "default");
+// => "x"
+
 ```
 ### identity
 
@@ -2421,6 +4973,7 @@ This method returns the first argument it receives.
 
 
 
+
 **Arguments:**
 
 @param mixed $value Any value.
@@ -2448,9 +5001,10 @@ Creates a function that returns the value at `path` of a given object.
 
 
 
+
 **Arguments:**
 
-@param array|string $ path The path of the property to get.
+@param (array | string) $path The path of the property to get.
 
 
 
@@ -2464,8 +5018,8 @@ Example:
  use function _\property;
 
 $objects = [
-  [ 'a' => [ 'b' => 2 ] ],
-  [ 'a' => [ 'b' => 1 ] ]
+[ 'a' => [ 'b' => 2 ] ],
+[ 'a' => [ 'b' => 1 ] ]
 ];
 
 map($objects, property('a.b'));
diff --git a/bin/compile b/bin/compile
new file mode 100755
index 0000000..1018030
--- /dev/null
+++ b/bin/compile
@@ -0,0 +1,36 @@
+#!/usr/bin/env php
+<?php
+
+// compiles all lodash functions into a single file
+
+declare(strict_types=1);
+
+function getCode(SplFileInfo $file): string
+{
+    $code = php_strip_whitespace($file->getRealPath());
+    $code = preg_replace(['#\<\?php#', '#declare\(strict_types=1\);#'], '', $code, 1);
+    $code = preg_replace('#namespace ([a-zA-Z\\\/-_0-9]+);\s?(.*)#', 'namespace $1 { $2 }', $code);
+
+    return $code;
+}
+
+$code = <<<CODE
+<?php
+
+// Auto-generated file
+
+
+CODE;
+
+$code .= '  namespace {'.str_replace("\n", '', getCode(new SplFileInfo(dirname(__DIR__).'/src/Lodash.php'))).' }';
+
+foreach (new RecursiveIteratorIterator(new RecursiveDirectoryIterator(dirname(__DIR__).'/src', RecursiveDirectoryIterator::SKIP_DOTS)) as $file) {
+    if (in_array($file->getBasename(), ['bootstrap.php', 'lodash.php', 'compiled.php', 'Lodash.php'], true)) {
+        continue;
+    }
+
+    $code .= getCode($file);
+}
+
+file_put_contents(dirname(__DIR__).'/src/compiled.php', $code);
+
diff --git a/bin/build b/bin/generate-readme
similarity index 56%
rename from bin/build
rename to bin/generate-readme
index 2b80eaa..a3d3419 100755
--- a/bin/build
+++ b/bin/generate-readme
@@ -1,11 +1,18 @@
 #!/usr/bin/env php
 <?php
 
+use PHPStan\PhpDocParser\Ast\PhpDoc\PhpDocChildNode;
+use PHPStan\PhpDocParser\Ast\PhpDoc\PhpDocTextNode;
+use PHPStan\PhpDocParser\Lexer\Lexer;
+use PHPStan\PhpDocParser\Parser\TokenIterator;
+
 require_once dirname(__DIR__).'/vendor/autoload.php';
 
 $sources = dirname(__DIR__).'/src';
 $factory = \phpDocumentor\Reflection\DocBlockFactory::createInstance();
 
+$parser = new PHPStan\PhpDocParser\Parser\PhpDocParser(new \PHPStan\PhpDocParser\Parser\TypeParser(), new \PHPStan\PhpDocParser\Parser\ConstExprParser());
+
 $readme = [];
 
 /** @var SplFileInfo $file */
@@ -23,40 +30,48 @@ foreach (new RecursiveIteratorIterator(new RecursiveDirectoryIterator($sources,
         continue;
     }
 
-    $reflection = new ReflectionFunction("_\\$function");
+    if (!\is_callable("_\\$function")) {
+        continue;
+    }
+
+    $reflection = new \ReflectionFunction("_\\$function");
 
-    $docblock = $factory->create($reflection->getDocComment());
+    $docblock = $parser->parse(new TokenIterator((new Lexer())->tokenize($reflection->getDocComment())));
 
-    $category = (string) $docblock->getTagsByName('category')[0];
+    $category = (string) current($docblock->getTagsByName('@category'))->value;
 
     $readme[$category][$function] = '';
 
     $readme[$category][$function] .= "### $function\n\n";
-    $readme[$category][$function] .= $docblock->getSummary().PHP_EOL.PHP_EOL;
-    $readme[$category][$function] .= $docblock->getDescription().PHP_EOL.PHP_EOL;
+
+    foreach (array_filter($docblock->children, function (PhpDocChildNode $child): bool {
+        return $child instanceof PhpDocTextNode;
+    }) as $text) {
+        $readme[$category][$function] .= (string) $text.PHP_EOL;
+    }
 
     $readme[$category][$function] .= "**Arguments:**\n\n";
 
-    foreach ($docblock->getTagsByName('param') as $param) {
-        $readme[$category][$function] .= $param->render().PHP_EOL.PHP_EOL;
+    foreach ($docblock->getTagsByName('@param') as $param) {
+        $readme[$category][$function] .= (string) $param.PHP_EOL.PHP_EOL;
     }
 
     $readme[$category][$function] .= PHP_EOL.PHP_EOL;
 
     $readme[$category][$function] .= "**Return:**\n\n";
 
-    $readme[$category][$function] .= $docblock->getTagsByName('return')[0]->render();
+    $readme[$category][$function] .= (string) current($docblock->getTagsByName('@return'));
 
     $readme[$category][$function] .= PHP_EOL.PHP_EOL;
 
-    if ($docblock->hasTag('example')) {
+    if (\preg_match('#<code>((.|\n)*?)</code>#', $readme[$category][$function], $matches)) {
+
+        $readme[$category][$function] = str_replace($matches[0], '', $readme[$category][$function]);
 
-        $example = str_replace(['<code>', '</code>'], '', $docblock->getTagsByName('example')[0] ?? '');
+        $example = $matches[1];
 
-        if ($example) {
-            $readme[$category][$function] .= "Example:\n```php\n<?php\n use function _\\$function;\n";
-            $readme[$category][$function] .= "$example\n```\n";
-        }
+        $readme[$category][$function] .= "Example:\n```php\n<?php\n use function _\\$function;\n";
+        $readme[$category][$function] .= "$example\n```\n";
     }
 }
 
@@ -74,7 +89,7 @@ Lodash-PHP tries to mimick lodash.js as close as possible
 Install Lodash-PHP through composer:
 
 ```bash
-$ composer require solidworx/lodash-php
+$ composer require lodash-php/lodash-php
 ```
 
 # Usage
@@ -121,4 +136,4 @@ foreach ($readme as $category => $functions) {
     }
 }
 
-file_put_contents(dirname(__DIR__).'/README.md', $content);
\ No newline at end of file
+file_put_contents(dirname(__DIR__).'/README.md', $content);
diff --git a/composer.json b/composer.json
index f82291f..35d299e 100644
--- a/composer.json
+++ b/composer.json
@@ -1,5 +1,5 @@
 {
-    "name": "solidworx/lodash-php",
+    "name": "lodash-php/lodash-php",
     "description": "A port of Lodash to PHP",
     "keywords": [
         "lodash",
@@ -19,17 +19,19 @@
     ],
     "autoload": {
         "files": [
-            "src/internal/unicode.php",
             "src/bootstrap.php"
         ]
     },
     "require": {
-        "php": "^7.1",
-        "sebastian/comparator": "^2.1",
-        "symfony/property-access": "^2.7 | ^3.0 | ^4.0"
+        "php": "^7.2 || ^8.0",
+        "sebastian/comparator": "^1.2 | ^2.0 | ^2.1 | ^3.0 | ^4.0 | ^5.0 | ^6.0",
+        "symfony/property-access": "^2.7 | ^3.0 | ^4.0 | ^5.0 | ^6.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^6.4",
-        "phpdocumentor/reflection-docblock": "^4.2"
+        "phpdocumentor/reflection-docblock": "*",
+        "phpstan/phpdoc-parser": "*",
+        "phpunit/phpunit": "^7.3 || ^8.4",
+        "phpstan/phpstan": "^1.10",
+        "friendsofphp/php-cs-fixer": "^2.12"
     }
 }
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
new file mode 100644
index 0000000..b806197
--- /dev/null
+++ b/phpstan-baseline.neon
@@ -0,0 +1,32 @@
+parameters:
+	ignoreErrors:
+		-
+			message: "#^Unreachable statement \\- code above always terminates\\.$#"
+			count: 1
+			path: src/Collection/size.php
+
+		-
+			message: "#^Right side of \\|\\| is always false\\.$#"
+			count: 2
+			path: src/Number/random.php
+
+		-
+			message: "#^Call to function is_array\\(\\) with null will always evaluate to false\\.$#"
+			count: 1
+			path: src/String/replace.php
+
+		-
+			message: "#^Comparison operation \"\\>\\=\" between int\\<0, max\\> and 0 is always true\\.$#"
+			count: 1
+			path: src/String/startsWith.php
+
+		-
+			message: "#^Offset mixed on \\*NEVER\\* in isset\\(\\) always exists and is not nullable\\.$#"
+			count: 1
+			path: src/internal/baseIntersection.php
+
+		-
+			message: "#^Unreachable statement \\- code above always terminates\\.$#"
+			count: 1
+			path: src/internal/isIterateeCall.php
+
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..08970a1
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,15 @@
+includes:
+    - phpstan-baseline.neon
+
+parameters:
+    paths:
+        - src
+    bootstrapFiles:
+        - src/bootstrap.php
+    level: 5
+    excludePaths:
+        - src/compiled.php
+        - src/Lodash.php
+        - src/internal/memoizeCapped.php # Exclude internal function due to dynamic class usage
+    ignoreErrors:
+        - "#^PHPDoc tag \\@param references unknown parameter\\: \\$[a-zA-Z]+$#"
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 3c500fe..192a663 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,8 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/6.4/phpunit.xsd"
-         backupGlobals="false"
+         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/7.3/phpunit.xsd"
          colors="true"
          bootstrap="vendor/autoload.php"
 >
diff --git a/src/Array/chunk.php b/src/Array/chunk.php
index 034349e..5e98626 100644
--- a/src/Array/chunk.php
+++ b/src/Array/chunk.php
@@ -38,4 +38,4 @@ function chunk(?array $array, int $number): array
     }
 
     return \array_chunk($array ?? [], $number, false);
-}
\ No newline at end of file
+}
diff --git a/src/Array/concat.php b/src/Array/concat.php
index 94a7465..945f2f8 100644
--- a/src/Array/concat.php
+++ b/src/Array/concat.php
@@ -17,8 +17,9 @@
  *
  * @category Array
  *
- * @param  array $array  The array to concatenate.
- * @param  mixed $values The values to concatenate.
+ * @param  array $array The array to concatenate.
+ * @param  array<int, mixed> $values The values to concatenate.
+ *
  * @return array Returns the new concatenated array.
  *
  * @example
@@ -26,10 +27,10 @@
  * $array = [1];
  * $other = concat($array, 2, [3], [[4]]);
  *
- * var_dump(other)
+ * var_dump($other)
  * // => [1, 2, 3, [4]]
  *
- * var_dump(array)
+ * var_dump($array)
  * // => [1]
  * </code>
  */
@@ -40,4 +41,4 @@ function concat($array, ...$values): array
     };
 
     return \array_merge($check($array), ...\array_map($check, $values));
-}
\ No newline at end of file
+}
diff --git a/src/Array/difference.php b/src/Array/difference.php
index ad15a4c..22c779c 100644
--- a/src/Array/difference.php
+++ b/src/Array/difference.php
@@ -21,8 +21,8 @@
  *
  * @category Array
  *
- * @param array   $array  The array to inspect.
- * @param mixed[] $values The values to exclude.
+ * @param array $array     The array to inspect.
+ * @param array ...$values The values to exclude.
  *
  * @return array Returns the new array of filtered values.
  *
@@ -35,4 +35,4 @@
 function difference(array $array, array ...$values): array
 {
     return \array_values(\array_diff($array, ...$values));
-}
\ No newline at end of file
+}
diff --git a/src/Array/differenceBy.php b/src/Array/differenceBy.php
index ba7aabd..8c5a7ca 100644
--- a/src/Array/differenceBy.php
+++ b/src/Array/differenceBy.php
@@ -24,16 +24,17 @@
  *
  * @category Array
  *
- * @param array $array  The array to inspect.
- * @param array $values The values to exclude.
- * @param callable iteratee The iteratee invoked per element.
+ * @param array    $array    The array to inspect.
+ * @param array<int, mixed> ...$values  The values to exclude.
+ * @param callable $iteratee The iteratee invoked per element.
  *
  * @return array Returns the new array of filtered values.
  *
  * @example
- *
+ * <code>
  * differenceBy([2.1, 1.2], [2.3, 3.4], 'floor')
  * // => [1.2]
+ * </code>
  */
 function differenceBy(array $array, ...$values): array
 {
@@ -45,6 +46,7 @@ function differenceBy(array $array, ...$values): array
         return difference($array, ...$values);
     }
 
+    /** @var callable $iteratee */
     $iteratee = \array_pop($values);
 
     $values = \array_map($iteratee, baseFlatten($values, 1, 'is_array', true, null));
@@ -65,4 +67,4 @@ function differenceBy(array $array, ...$values): array
     }
 
     return $result;
-}
\ No newline at end of file
+}
diff --git a/src/Array/differenceWith.php b/src/Array/differenceWith.php
index d64ea02..912e117 100644
--- a/src/Array/differenceWith.php
+++ b/src/Array/differenceWith.php
@@ -23,11 +23,14 @@
  *
  * @category Array
  *
- * @param array    $array      The array to inspect.
- * @param array[] $values The values to exclude.
+ * @param array<int, mixed>    $array      The array to inspect.
+ * @param array    ...$values  The values to exclude.
  * @param callable $comparator The comparator invoked per element.
  *
  * @return array Returns the new array of filtered values.
+ *
+ * @throws \InvalidArgumentException
+ *
  * @example
  * <code>
  * $objects = [[ 'x' => 1, 'y' => 2 ], [ 'x' => 2, 'y' => 1 ]]
@@ -46,6 +49,7 @@ function differenceWith(array $array, ...$values): array
         return difference($array, ...$values);
     }
 
+    /** @var callable $comparator */
     $comparator = \array_pop($values);
 
     $values = baseFlatten($values, 1, 'is_array', true, null);
@@ -65,4 +69,4 @@ function differenceWith(array $array, ...$values): array
     }
 
     return $result;
-}
\ No newline at end of file
+}
diff --git a/src/Array/drop.php b/src/Array/drop.php
index 4b3e53e..86bd80b 100644
--- a/src/Array/drop.php
+++ b/src/Array/drop.php
@@ -40,4 +40,4 @@
 function drop(array $array, int $n = 1): array
 {
     return \array_slice($array, $n);
-}
\ No newline at end of file
+}
diff --git a/src/Array/dropRight.php b/src/Array/dropRight.php
index 69d2177..3e578e3 100644
--- a/src/Array/dropRight.php
+++ b/src/Array/dropRight.php
@@ -45,4 +45,4 @@ function dropRight(array $array, int $n = 1): array
     }
 
     return \array_slice($array, 0, $count - $n);
-}
\ No newline at end of file
+}
diff --git a/src/Array/dropRightWhile.php b/src/Array/dropRightWhile.php
index 76df132..b637215 100644
--- a/src/Array/dropRightWhile.php
+++ b/src/Array/dropRightWhile.php
@@ -47,4 +47,4 @@ function dropRightWhile(array $array, callable $predicate): array
     }
 
     return $array;
-}
\ No newline at end of file
+}
diff --git a/src/Array/dropWhile.php b/src/Array/dropWhile.php
index e0f0d41..36020df 100644
--- a/src/Array/dropWhile.php
+++ b/src/Array/dropWhile.php
@@ -40,12 +40,14 @@ function dropWhile(array $array, callable $predicate): array
     $count = \count($array);
     $length = 0;
     $index = \key($array);
-    while ($length <= $count && $predicate($array[$index], $index, $array)) {
+    $value = \current($array);
+    while ($length <= $count && $predicate($value, $index, $array)) {
         array_shift($array);
         \reset($array);
         $length++;
         $index = \key($array);
+        $value = \current($array);
     }
 
     return $array;
-}
\ No newline at end of file
+}
diff --git a/src/Array/findIndex.php b/src/Array/findIndex.php
index 04cb61d..36b9737 100644
--- a/src/Array/findIndex.php
+++ b/src/Array/findIndex.php
@@ -70,4 +70,4 @@ function findIndex(array $array, $predicate, int $fromIndex = null): int
     }
 
     return -1;
-}
\ No newline at end of file
+}
diff --git a/src/Array/findLastIndex.php b/src/Array/findLastIndex.php
index 1bf43e2..a8f32f5 100644
--- a/src/Array/findLastIndex.php
+++ b/src/Array/findLastIndex.php
@@ -55,4 +55,4 @@ function findLastIndex(array $array, $predicate, int $fromIndex = null): int
     }
 
     return -1;
-}
\ No newline at end of file
+}
diff --git a/src/Array/flatten.php b/src/Array/flatten.php
index 46eb08f..be6371b 100644
--- a/src/Array/flatten.php
+++ b/src/Array/flatten.php
@@ -22,11 +22,12 @@
  *
  * @return array the new flattened array.
  * @example
- *
+ * <code>
  * flatten([1, [2, [3, [4]], 5]])
  * // => [1, 2, [3, [4]], 5]
+ * </code>
  */
 function flatten(array $array = null): array
 {
     return baseFlatten($array, 1);
-}
\ No newline at end of file
+}
diff --git a/src/Array/flattenDeep.php b/src/Array/flattenDeep.php
index 73c62f6..61a9933 100644
--- a/src/Array/flattenDeep.php
+++ b/src/Array/flattenDeep.php
@@ -29,5 +29,5 @@
  */
 function flattenDeep(array $array): array
 {
-    return baseFlatten($array, INF);
-}
\ No newline at end of file
+    return baseFlatten($array, PHP_INT_MAX);
+}
diff --git a/src/Array/flattenDepth.php b/src/Array/flattenDepth.php
index 9f96b44..27e07e6 100644
--- a/src/Array/flattenDepth.php
+++ b/src/Array/flattenDepth.php
@@ -36,4 +36,4 @@
 function flattenDepth(array $array, int $depth = 1): array
 {
     return baseFlatten($array, $depth);
-}
\ No newline at end of file
+}
diff --git a/src/Array/fromPairs.php b/src/Array/fromPairs.php
index 6384743..7541e04 100644
--- a/src/Array/fromPairs.php
+++ b/src/Array/fromPairs.php
@@ -19,7 +19,8 @@
  *
  * @param array $pairs The key-value pairs.
  *
- * @return object the new object.
+ * @return \stdClass the new object.
+ *
  * @example
  * <code>
  * fromPairs([['a', 1], ['b', 2]])
@@ -42,4 +43,4 @@ function fromPairs(array $pairs): \stdClass
     }
 
     return $result;
-}
\ No newline at end of file
+}
diff --git a/src/Array/head.php b/src/Array/head.php
index ecdeb5f..b8bd6a8 100644
--- a/src/Array/head.php
+++ b/src/Array/head.php
@@ -41,4 +41,4 @@ function head(array $array)
 function first(array $array)
 {
     return head($array);
-}
\ No newline at end of file
+}
diff --git a/src/Array/indexOf.php b/src/Array/indexOf.php
index ac1e8bc..db81dbe 100644
--- a/src/Array/indexOf.php
+++ b/src/Array/indexOf.php
@@ -56,4 +56,4 @@ function indexOf(array $array, $value, int $fromIndex = null): int
     }
 
     return -1;
-}
\ No newline at end of file
+}
diff --git a/src/Array/initial.php b/src/Array/initial.php
index 9e7f1eb..8368454 100644
--- a/src/Array/initial.php
+++ b/src/Array/initial.php
@@ -20,12 +20,13 @@
  *
  * @return array the slice of `array`.
  * @example
- *
+ * <code>
  * initial([1, 2, 3])
  * // => [1, 2]
+ * </code>
  */
 function initial(array $array): array
 {
     \array_pop($array);
     return $array;
-}
\ No newline at end of file
+}
diff --git a/src/Array/intersection.php b/src/Array/intersection.php
index 99d2cf1..6d05520 100644
--- a/src/Array/intersection.php
+++ b/src/Array/intersection.php
@@ -19,15 +19,17 @@
  *
  * @category Array
  *
- * @param array[] $arrays
+ * @param array ...$arrays
  *
  * @return array the new array of intersecting values.
- * @example
  *
+ * @example
+ * <code>
  * intersection([2, 1], [2, 3])
  * // => [2]
+ * </code>
  */
 function intersection(array ...$arrays): array
 {
     return \array_intersect(...$arrays);
-}
\ No newline at end of file
+}
diff --git a/src/Array/intersectionBy.php b/src/Array/intersectionBy.php
index e1177b3..44ca1c5 100644
--- a/src/Array/intersectionBy.php
+++ b/src/Array/intersectionBy.php
@@ -23,7 +23,7 @@
  *
  * @category Array
  *
- * @param array[]  $arrays
+ * @param array<int, mixed>  ...$arrays
  * @param callable $iteratee The iteratee invoked per element.
  *
  * @return array the new array of intersecting values.
@@ -42,4 +42,4 @@ function intersectionBy(...$arrays/*, callable $iteratee*/): array
     $iteratee = \array_pop($arrays);
 
     return baseIntersection($arrays, baseIteratee($iteratee));
-}
\ No newline at end of file
+}
diff --git a/src/Array/intersectionWith.php b/src/Array/intersectionWith.php
index a2eac29..be8dbd4 100644
--- a/src/Array/intersectionWith.php
+++ b/src/Array/intersectionWith.php
@@ -21,10 +21,11 @@
  *
  * @category Array
  *
- * @param array[]  $arrays
+ * @param array    ...$arrays
  * @param callable $comparator The comparator invoked per element.
  *
  * @return array the new array of intersecting values.
+ *
  * @example
  * <code>
  * $objects = [[ 'x' => 1, 'y' => 2 ], [ 'x' => 2, 'y' => 1 ]]
@@ -37,7 +38,7 @@
 function intersectionWith(...$arrays /*, callable $comparator = null*/): array
 {
     $copy = $arrays;
-    $comparator = array_pop($arrays);
+    $comparator = \array_pop($arrays);
 
     if (!\is_callable($comparator)) {
         $arrays = $copy;
@@ -45,4 +46,4 @@ function intersectionWith(...$arrays /*, callable $comparator = null*/): array
     }
 
     return baseIntersection($arrays, null, $comparator);
-}
\ No newline at end of file
+}
diff --git a/src/Array/last.php b/src/Array/last.php
index 45f2628..77ff437 100644
--- a/src/Array/last.php
+++ b/src/Array/last.php
@@ -28,4 +28,4 @@
 function last(array $array)
 {
     return \end($array) ?: null;
-}
\ No newline at end of file
+}
diff --git a/src/Array/lastIndexOf.php b/src/Array/lastIndexOf.php
index 42498f8..f1ba610 100644
--- a/src/Array/lastIndexOf.php
+++ b/src/Array/lastIndexOf.php
@@ -50,4 +50,4 @@ function lastIndexOf(array $array, $value, int $fromIndex = null): int
     }
 
     return -1;
-}
\ No newline at end of file
+}
diff --git a/src/Array/nth.php b/src/Array/nth.php
index 61c5842..4b037fa 100644
--- a/src/Array/nth.php
+++ b/src/Array/nth.php
@@ -22,7 +22,7 @@
  *
  * @return mixed Returns the nth element of `array`.
  * @example
- *
+ * <code>
  * $array = ['a', 'b', 'c', 'd']
  *
  * nth($array, 1)
@@ -30,8 +30,9 @@
  *
  * nth($array, -2)
  * // => 'c'
+ * </code>
  */
 function nth(array $array, int $n)
 {
     return \array_values($array)[$n < 0 ? \count($array) + $n : $n] ?? null;
-}
\ No newline at end of file
+}
diff --git a/src/Array/pull.php b/src/Array/pull.php
index aca39a5..f585be2 100644
--- a/src/Array/pull.php
+++ b/src/Array/pull.php
@@ -21,10 +21,11 @@
  *
  * @category Array
  *
- * @param array   $array  The array to modify.
- * @param mixed[] $values The values to remove.
+ * @param array $array The array to modify.
+ * @param array<int, string> $values The values to remove.
  *
  * @return array
+ *
  * @example
  * <code>
  * $array = ['a', 'b', 'c', 'a', 'b', 'c']
@@ -43,4 +44,4 @@ function pull(array &$array, ...$values): array
     $array = \array_values($array); // Re-index array
 
     return $array;
-}
\ No newline at end of file
+}
diff --git a/src/Array/pullAll.php b/src/Array/pullAll.php
index b15b023..d2880b9 100644
--- a/src/Array/pullAll.php
+++ b/src/Array/pullAll.php
@@ -34,4 +34,4 @@
 function pullAll(array &$array, array $values): array
 {
     return pull($array, ...$values);
-}
\ No newline at end of file
+}
diff --git a/src/Array/pullAllBy.php b/src/Array/pullAllBy.php
index f871245..5e50a76 100644
--- a/src/Array/pullAllBy.php
+++ b/src/Array/pullAllBy.php
@@ -29,14 +29,15 @@
  *
  * @return array `array`.
  * @example
- *
+ * <code>
  * $array = [[ 'x' => 1 ], [ 'x' => 2 ], [ 'x' => 3 ], [ 'x' => 1 ]]
  *
  * pullAllBy($array, [[ 'x' => 1 ], [ 'x' => 3 ]], 'x')
  * var_dump($array)
  * // => [[ 'x' => 2 ]]
+ * </code>
  */
 function pullAllBy(array &$array, array $values, $iteratee): array
 {
     return basePullAll($array, $values, baseIteratee($iteratee));
-}
\ No newline at end of file
+}
diff --git a/src/Array/pullAllWith.php b/src/Array/pullAllWith.php
index c5088bb..2c9c20b 100644
--- a/src/Array/pullAllWith.php
+++ b/src/Array/pullAllWith.php
@@ -39,4 +39,4 @@
 function pullAllWith(array &$array, array $values, callable $comparator): array
 {
     return basePullAll($array, $values, null, $comparator);
-}
\ No newline at end of file
+}
diff --git a/src/Array/pullAt.php b/src/Array/pullAt.php
index 6fd5f3f..19e53bc 100644
--- a/src/Array/pullAt.php
+++ b/src/Array/pullAt.php
@@ -53,4 +53,4 @@ function pullAt(array &$array, $indexes): array
     $array = \array_values($array);
 
     return $pulled;
-}
\ No newline at end of file
+}
diff --git a/src/Array/remove.php b/src/Array/remove.php
index df7dae1..a939bf5 100644
--- a/src/Array/remove.php
+++ b/src/Array/remove.php
@@ -26,7 +26,7 @@
  *
  * @return array the new array of removed elements.
  * @example
- *
+ * <code>
  * $array = [1, 2, 3, 4]
  * $evens = remove($array, function ($n) { return $n % 2 === 0; })
  *
@@ -35,6 +35,7 @@
  *
  * var_dump($evens)
  * // => [2, 4]
+ * </code>
  */
 function remove(array &$array, callable $predicate): array
 {
@@ -52,4 +53,4 @@ function remove(array &$array, callable $predicate): array
     $array = \array_values($array); // Re-index array
 
     return $resultArray;
-}
\ No newline at end of file
+}
diff --git a/src/Array/slice.php b/src/Array/slice.php
index e882e83..33382db 100644
--- a/src/Array/slice.php
+++ b/src/Array/slice.php
@@ -25,4 +25,4 @@
 function slice(array $array, int $start, int $end = null): array
 {
     return \array_slice($array, $start, $end);
-}
\ No newline at end of file
+}
diff --git a/src/Array/tail.php b/src/Array/tail.php
new file mode 100644
index 0000000..085e287
--- /dev/null
+++ b/src/Array/tail.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Gets all but the first element of `array`.
+ *
+ * @category Array
+ *
+ * @param array $array The array to query.
+ *
+ * @return array the slice of `array`.
+ *
+ * @example
+ * <code>
+ * tail([1, 2, 3])
+ * // => [2, 3]
+ * </code>
+ */
+function tail(array $array): array
+{
+    array_shift($array);
+
+    return $array;
+}
diff --git a/src/Array/take.php b/src/Array/take.php
new file mode 100644
index 0000000..7f7d9dc
--- /dev/null
+++ b/src/Array/take.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a slice of `array` with `n` elements taken from the beginning.
+ *
+ * @category Array
+ *
+ * @param array $array The array to query.
+ * @param int   $n     The number of elements to take.
+ *
+ * @return array the slice of `array`.
+ * @example
+ * <code>
+ * take([1, 2, 3])
+ * // => [1]
+ *
+ * take([1, 2, 3], 2)
+ * // => [1, 2]
+ *
+ * take([1, 2, 3], 5)
+ * // => [1, 2, 3]
+ *
+ * take([1, 2, 3], 0)
+ * // => []
+ * </code>
+ */
+function take(array $array, int $n = 1): array
+{
+    if (1 > $n) {
+        return [];
+    }
+
+    array_splice($array, $n);
+
+    return $array;
+}
diff --git a/src/Array/takeRight.php b/src/Array/takeRight.php
new file mode 100644
index 0000000..1655c6d
--- /dev/null
+++ b/src/Array/takeRight.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a slice of `array` with `n` elements taken from the end.
+ *
+ * @category Array
+ *
+ * @param array $array The array to query.
+ * @param int   $n     The number of elements to take.
+ *
+ * @return array the slice of `array`.
+ * @example
+ * <code>
+ * takeRight([1, 2, 3])
+ * // => [3]
+ *
+ * takeRight([1, 2, 3], 2)
+ * // => [2, 3]
+ *
+ * takeRight([1, 2, 3], 5)
+ * // => [1, 2, 3]
+ *
+ * takeRight([1, 2, 3], 0)
+ * // => []
+ * </code>
+ */
+function takeRight(array $array, int $n = 1): array
+{
+    if (1 > $n) {
+        return [];
+    }
+
+    return array_slice($array, -$n);
+}
diff --git a/src/Array/takeRightWhile.php b/src/Array/takeRightWhile.php
new file mode 100644
index 0000000..da898ba
--- /dev/null
+++ b/src/Array/takeRightWhile.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * Creates a slice of `array` with elements taken from the end. Elements are
+ * taken until `predicate` returns falsey. The predicate is invoked with
+ * three arguments: (value, index, array).
+ *
+ * @category Array
+ *
+ * @param array    $array     The array to query.
+ * @param callable $predicate The function invoked per iteration.
+ *
+ * @return array the slice of `array`.
+ *
+ * @example
+ * <code>
+ * $users = [
+ *   [ 'user' => 'barney',  'active' => false ],
+ *   [ 'user' => 'fred',    'active' => true ],
+ *   [ 'user' => 'pebbles', 'active' => true ]
+ * ];
+ *
+ * takeRightWhile($users, function($value) { return $value['active']; })
+ * // => objects for ['fred', 'pebbles']
+ * </code>
+ */
+function takeRightWhile(array $array, $predicate): array
+{
+    $iteratee = baseIteratee($predicate);
+    $result = [];
+
+    foreach (array_reverse($array, true) as $index => $value) {
+        if ($iteratee($value, $index, $array)) {
+            $result[$index] = $value;
+        }
+    }
+
+    return array_reverse($result);
+}
diff --git a/src/Array/takeWhile.php b/src/Array/takeWhile.php
new file mode 100644
index 0000000..6e6218f
--- /dev/null
+++ b/src/Array/takeWhile.php
@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * Creates a slice of `array` with elements taken from the beginning. Elements
+ * are taken until `predicate` returns falsey. The predicate is invoked with
+ * three arguments: (value, index, array).
+ *
+ * @category Array
+ *
+ * @param array $array     The array to query.
+ * @param mixed $predicate The function invoked per iteration.
+ *
+ * @return array the slice of `array`.
+ *
+ * @example
+ * <code>
+ * $users = [
+ *   [ 'user' => 'barney',  'active' => true ],
+ *   [ 'user' => 'fred',    'active' => true ],
+ *   [ 'user' => 'pebbles', 'active' => false ]
+ * ]
+ *
+ * takeWhile($users, function($value) { return $value['active']; })
+ * // => objects for ['barney', 'fred']
+ * </code>
+ */
+function takeWhile(array $array, $predicate): array
+{
+    $result = [];
+
+    $iteratee = baseIteratee($predicate);
+
+    foreach ($array as $index => $value) {
+        if ($iteratee($value, $index, $array)) {
+            $result[$index] = $value;
+        }
+    }
+
+    return $result;
+}
diff --git a/src/Array/union.php b/src/Array/union.php
new file mode 100644
index 0000000..e02f4f7
--- /dev/null
+++ b/src/Array/union.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates an array of unique values, in order, from all given arrays using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+ * for equality comparisons.
+ *
+ * @category Array
+ *
+ * @param array ...$arrays The arrays to inspect.
+ *
+ * @return array the new array of combined values.
+ *
+ * @example
+ * <code>
+ * union([2], [1, 2])
+ * // => [2, 1]
+ * </code>
+ */
+function union(array ...$arrays): array
+{
+    return array_unique(array_merge(...$arrays));
+}
diff --git a/src/Array/unionBy.php b/src/Array/unionBy.php
new file mode 100644
index 0000000..af400c6
--- /dev/null
+++ b/src/Array/unionBy.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseFlatten;
+use function _\internal\baseIteratee;
+use function _\internal\baseUniq;
+
+/**
+ * This method is like `union` except that it accepts `iteratee` which is
+ * invoked for each element of each `arrays` to generate the criterion by
+ * which uniqueness is computed. Result values are chosen from the first
+ * array in which the value occurs. The iteratee is invoked with one argument:
+ * (value).
+ *
+ * @category Array
+ *
+ * @param array<int, mixed>    ...$arrays The arrays to inspect.
+ * @param callable $iteratee  The iteratee invoked per element.
+ *
+ * @return array the new array of combined values.
+ *
+ * @example
+ * <code>
+ * unionBy([2.1], [1.2, 2.3], 'floor')
+ * // => [2.1, 1.2]
+ *
+ * // The `_::property` iteratee shorthand.
+ * unionBy([['x' => 1]], [['x' => 2], ['x' => 1]], 'x');
+ * // => [['x' => 1], ['x' => 2]]
+ * </code>
+ */
+function unionBy(...$arrays): array
+{
+    return baseUniq(baseFlatten($arrays, 1, '\is_array', true), baseIteratee(\array_pop($arrays)));
+}
diff --git a/src/Array/unionWith.php b/src/Array/unionWith.php
new file mode 100644
index 0000000..56b2071
--- /dev/null
+++ b/src/Array/unionWith.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseFlatten;
+use function _\internal\baseUniq;
+
+/**
+ * This method is like `union` except that it accepts `comparator` which
+ * is invoked to compare elements of `arrays`. Result values are chosen from
+ * the first array in which the value occurs. The comparator is invoked
+ * with two arguments: (arrVal, othVal).
+ *
+ * @category Array
+ *
+ * @param array<int, mixed>    ...$arrays  The arrays to inspect.
+ * @param callable $comparator The comparator invoked per element.
+ *
+ * @return array the new array of combined values.
+ *
+ * @throws \InvalidArgumentException
+ *
+ * @example
+ * <code>
+ * $objects = [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1]]
+ * $others = [['x' => 1, 'y' => 1], ['x' => 1, 'y' => 2]]
+ *
+ * unionWith($objects, $others, '_::isEqual')
+ * // => [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1], ['x' => 1, 'y' => 1]]
+ * </code>
+ */
+function unionWith(... $arrays): array
+{
+    /** @var callable $comparator */
+    $comparator = \array_pop($arrays);
+
+    if (!\is_callable($comparator)) {
+        throw new \InvalidArgumentException(__FUNCTION__.' expects the last value passed to be callable');
+    }
+
+    return baseUniq(baseFlatten($arrays, 1, '\is_array', true), null, $comparator);
+}
diff --git a/src/Array/uniq.php b/src/Array/uniq.php
new file mode 100644
index 0000000..4aa7515
--- /dev/null
+++ b/src/Array/uniq.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a duplicate-free version of an array, using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+ * for equality comparisons, in which only the first occurrence of each element
+ * is kept. The order of result values is determined by the order they occur
+ * in the array.
+ *
+ * @category Array
+ *
+ * @param array $array The array to inspect.
+ *
+ * @return array the new duplicate free array.
+ * @example
+ * <code>
+ * uniq([2, 1, 2])
+ * // => [2, 1]s
+ * </code>
+ */
+function uniq(array $array = []): array
+{
+    return \array_unique($array);
+}
diff --git a/src/Array/uniqBy.php b/src/Array/uniqBy.php
new file mode 100644
index 0000000..012d557
--- /dev/null
+++ b/src/Array/uniqBy.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+use function _\internal\baseUniq;
+
+/**
+ * This method is like `uniq` except that it accepts `iteratee` which is
+ * invoked for each element in `array` to generate the criterion by which
+ * uniqueness is computed. The order of result values is determined by the
+ * order they occur in the array. The iteratee is invoked with one argument:
+ * (value).
+ *
+ * @category Array
+ *
+ * @param array $array    The array to inspect.
+ * @param mixed $iteratee The iteratee invoked per element.
+ *
+ * @return array the new duplicate free array.
+ * @example
+ * <code>
+ * uniqBy([2.1, 1.2, 2.3], 'floor')
+ * // => [2.1, 1.2]
+ * </code>
+ */
+function uniqBy(array $array, $iteratee): array
+{
+    return baseUniq($array, baseIteratee($iteratee));
+}
diff --git a/src/Array/uniqWith.php b/src/Array/uniqWith.php
new file mode 100644
index 0000000..0f98a2c
--- /dev/null
+++ b/src/Array/uniqWith.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseUniq;
+
+/**
+ * This method is like `uniq` except that it accepts `comparator` which
+ * is invoked to compare elements of `array`. The order of result values is
+ * determined by the order they occur in the array.The comparator is invoked
+ * with two arguments: (arrVal, othVal).
+ *
+ * @category Array
+ *
+ * @param array    $array      The array to inspect.
+ * @param callable $comparator The comparator invoked per element.
+ *
+ * @return array the new duplicate free array.
+ * @example
+ * <code>
+ * $objects = [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1], ['x' => 1, 'y' => 2]]
+ *
+ * uniqWith($objects, '_::isEqual')
+ * // => [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1]]
+ * </code>
+ */
+function uniqWith(array $array, callable $comparator): array
+{
+    return baseUniq($array, null, $comparator);
+}
diff --git a/src/Array/unzip.php b/src/Array/unzip.php
new file mode 100644
index 0000000..60c24e5
--- /dev/null
+++ b/src/Array/unzip.php
@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\arrayMap;
+use function _\internal\baseProperty;
+use function _\internal\baseTimes;
+
+/**
+ * This method is like `zip` except that it accepts an array of grouped
+ * elements and creates an array regrouping the elements to their pre-zip
+ * configuration.
+ *
+ * @category Array
+ *
+ * @param array $array The array of grouped elements to process.
+ *
+ * @return array the new array of regrouped elements.
+ * @example
+ * <code>
+ * $zipped = zip(['a', 'b'], [1, 2], [true, false])
+ * // => [['a', 1, true], ['b', 2, false]]
+ *
+ * unzip($zipped)
+ * // => [['a', 'b'], [1, 2], [true, false]]
+ * </code>
+ */
+function unzip(array $array): array
+{
+    if (!\count($array)) {
+        return [];
+    }
+
+    $length = 0;
+    $array = \array_filter($array, function ($group) use (&$length) {
+        if (\is_array($group)) {
+            $length = \max(\count($group), $length);
+
+            return true;
+        }
+    });
+
+    return baseTimes($length, function ($index) use ($array) {
+        return arrayMap($array, baseProperty($index));
+    });
+}
diff --git a/src/Array/unzipWith.php b/src/Array/unzipWith.php
new file mode 100644
index 0000000..17365f8
--- /dev/null
+++ b/src/Array/unzipWith.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\arrayMap;
+
+/**
+ * This method is like `unzip` except that it accepts `iteratee` to specify
+ * how regrouped values should be combined. The iteratee is invoked with the
+ * elements of each group: (...group).
+ *
+ * @category Array
+ *
+ * @param array         $array    The array of grouped elements to process.
+ * @param callable|null $iteratee The function to combine regrouped values.
+ *
+ * @return array the new array of regrouped elements.
+ *
+ * @example
+ * <code>
+ * $zipped = zip([1, 2], [10, 20], [100, 200])
+ * // => [[1, 10, 100], [2, 20, 200]]
+ *
+ * unzipWith(zipped, '_::add')
+ * // => [3, 30, 300]
+ * </code>
+ */
+function unzipWith(array $array, ?callable $iteratee = null): array
+{
+    if (!\count($array)) {
+        return [];
+    }
+
+    $result = unzip($array);
+    if (!is_callable($iteratee)) {
+        return $result;
+    }
+
+    return arrayMap($result, function ($group) use ($iteratee) {
+        return $iteratee(...$group);
+    });
+}
diff --git a/src/Array/without.php b/src/Array/without.php
new file mode 100644
index 0000000..7976e97
--- /dev/null
+++ b/src/Array/without.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseRest;
+
+/**
+ * Creates an array excluding all given values using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+ * for equality comparisons.
+ *
+ * **Note:** Unlike `pull`, this method returns a new array.
+ *
+ * @category Array
+ *
+ * @param array $array The array to inspect.
+ * @param array<int, mixed> $values The values to exclude.
+ *
+ * @return array the new array of filtered values.
+ * @example
+ * <code>
+ * without([2, 1, 2, 3], 1, 2)
+ * // => [3]
+ * </code>
+ */
+function without(array $array, ...$values): array
+{
+    return baseRest('\_\difference')($array, ...$values);
+}
diff --git a/src/Array/zip.php b/src/Array/zip.php
new file mode 100644
index 0000000..24c8cbd
--- /dev/null
+++ b/src/Array/zip.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseRest;
+
+/**
+ * Creates an array of grouped elements, the first of which contains the
+ * first elements of the given arrays, the second of which contains the
+ * second elements of the given arrays, and so on.
+ *
+ * @category Array
+ *
+ * @param array ...$arrays The arrays to process.
+ *
+ * @return array the new array of grouped elements.
+ * @example
+ * <code>
+ * zip(['a', 'b'], [1, 2], [true, false])
+ * // => [['a', 1, true], ['b', 2, false]]
+ * </code>
+ */
+function zip(array ...$arrays): array
+{
+    return baseRest('\_\unzip')(...$arrays);
+}
diff --git a/src/Array/zipObject.php b/src/Array/zipObject.php
new file mode 100644
index 0000000..69fd505
--- /dev/null
+++ b/src/Array/zipObject.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * This method is like `fromPairs` except that it accepts two arrays,
+ * one of property identifiers and one of corresponding values.
+ *
+ * @category Array
+ *
+ * @param array $props  The property identifiers.
+ * @param array $values The property values.
+ *
+ * @return object the new object.
+ *
+ * @example
+ * <code>
+ * zipObject(['a', 'b'], [1, 2])
+ * /* => object(stdClass)#210 (2) {
+ * ["a"] => int(1)
+ * ["b"] => int(2)
+ * }
+ * *\/
+ * </code>
+ */
+function zipObject(array $props = [], array $values = [])
+{
+    $result = new \stdClass;
+    $index = -1;
+    $length = \count($props);
+    $props = \array_values($props);
+    $values = \array_values($values);
+
+    while (++$index < $length) {
+        $value = $values[$index] ?? null;
+        $result->{$props[$index]} = $value;
+    }
+
+    return $result;
+}
diff --git a/src/Array/zipObjectDeep.php b/src/Array/zipObjectDeep.php
new file mode 100644
index 0000000..dd8defc
--- /dev/null
+++ b/src/Array/zipObjectDeep.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseSet;
+
+/**
+ * This method is like `zipObject` except that it supports property paths.
+ *
+ * @category Array
+ *
+ * @param array $props  The property identifiers.
+ * @param array $values The property values.
+ *
+ * @return \stdClass the new object.
+ *
+ * @example
+ * <code>
+ * zipObjectDeep(['a.b[0].c', 'a.b[1].d'], [1, 2])
+ * /* => class stdClass#20 (1) {
+ *  public $a => class stdClass#19 (1) {
+ *      public $b =>
+ *          array(2) {
+ *              [0] => class stdClass#17 (1) {
+ *                      public $c => int(1)
+ *                  }
+ *             [1] => class stdClass#18 (1) {
+ *                  public $d => int(2)
+ *                  }
+ *          }
+ *      }
+ *  }
+ * *\/
+ * </code>
+ */
+function zipObjectDeep(array $props = [], array $values = []): \stdClass
+{
+    $result = new \stdClass;
+    $index = -1;
+    $length = \count($props);
+    $props = \array_values($props);
+    $values = \array_values($values);
+
+    while (++$index < $length) {
+        $value = $values[$index] ?? null;
+        baseSet($result, $props[$index], $value);
+    }
+
+    return $result;
+}
diff --git a/src/Array/zipWith.php b/src/Array/zipWith.php
new file mode 100644
index 0000000..58727f0
--- /dev/null
+++ b/src/Array/zipWith.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * This method is like `zip` except that it accepts `iteratee` to specify
+ * how grouped values should be combined. The iteratee is invoked with the
+ * elements of each group: (...group).
+ *
+ * @category Array
+ *
+ * @param array<int, array|callable>  ...$arrays   The arrays to process.
+ * @param callable $iteratee The function to combine grouped values.
+ *
+ * @return array the new array of grouped elements.
+ *
+ * @example
+ * <code>
+ * zipWith([1, 2], [10, 20], [100, 200], function($a, $b, $c) { return $a + $b + $c; })
+ * // => [111, 222]
+ * </code>
+ */
+function zipWith(...$arrays): array
+{
+    /** @var callable|null $iteratee */
+    $iteratee = \is_callable(\end($arrays)) ? \array_pop($arrays) : null;
+
+    return unzipWith($arrays, $iteratee);
+}
diff --git a/src/CacheInterface.php b/src/CacheInterface.php
new file mode 100644
index 0000000..096a0b7
--- /dev/null
+++ b/src/CacheInterface.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+interface CacheInterface
+{
+    public function set($key, $value): CacheInterface;
+
+    public function get($key);
+
+    public function has($key): bool;
+
+    public function clear();
+
+    public function delete($key);
+
+    public function getSize();
+}
diff --git a/src/Collection/countBy.php b/src/Collection/countBy.php
new file mode 100644
index 0000000..ae2dd51
--- /dev/null
+++ b/src/Collection/countBy.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\createAggregator;
+
+/**
+ * Creates an array composed of keys generated from the results of running
+ * each element of `collection` through `iteratee`. The corresponding value of
+ * each key is the number of times the key was returned by `iteratee`. The
+ * iteratee is invoked with one argument: (value).
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to iterate over.
+ * @param callable $iteratee   The iteratee to transform keys.
+ *
+ * @return array Returns the composed aggregate object.
+ * @example
+ * <code>
+ * countBy([6.1, 4.2, 6.3], 'floor');
+ * // => ['6' => 2, '4' => 1]
+ *
+ * // The `property` iteratee shorthand.
+ * countBy(['one', 'two', 'three'], 'strlen');
+ * // => ['3' => 2, '5' => 1]
+ * </code>
+ */
+function countBy(iterable $collection, callable $iteratee): array
+{
+    return createAggregator(function ($result, $key, $value) {
+        if (!isset($result[$value])) {
+            $result[$value] = 0;
+        }
+
+        $result[$value]++;
+
+        return $result;
+    })($collection, $iteratee);
+}
diff --git a/src/Collection/each.php b/src/Collection/each.php
index 123009b..a78a041 100644
--- a/src/Collection/each.php
+++ b/src/Collection/each.php
@@ -22,11 +22,11 @@
  *
  * @category     Collection
  *
- * @param array|object $collection The collection to iterate over.
- * @param callable     $iteratee   The function invoked per iteration.
+ * @param array|iterable|object $collection The collection to iterate over.
+ * @param callable              $iteratee   The function invoked per iteration.
  *
  * @return array|object Returns `collection`.
- * @related forEachRight, forIn, forInRight, forOwn, forOwnRight
+ *
  * @example
  * <code>
  * each([1, 2], function ($value) { echo $value; })
@@ -38,12 +38,9 @@
  */
 function each($collection, callable $iteratee)
 {
-    $values = $collection;
-
-    if (\is_object($collection)) {
-        $values = \get_object_vars($collection);
-    }
+    $values = \is_object($collection) ? \get_object_vars($collection) : $collection;
 
+    /** @var array $values */
     foreach ($values as $index => $value) {
         if (false === $iteratee($value, $index, $collection)) {
             break;
@@ -51,4 +48,4 @@ function each($collection, callable $iteratee)
     }
 
     return $collection;
-}
\ No newline at end of file
+}
diff --git a/src/Collection/eachRight.php b/src/Collection/eachRight.php
new file mode 100644
index 0000000..94d3130
--- /dev/null
+++ b/src/Collection/eachRight.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * This method is like `each` except that it iterates over elements of
+ * `collection` from right to left.
+ *
+ * @category Collection
+ *
+ * @param array|iterable|object $collection The collection to iterate over.
+ * @param callable              $iteratee   The function invoked per iteration.
+ *
+ * @return array|object Returns `collection`.
+ * @example
+ * <code>
+ * eachRight([1, 2], function($value) { echo $value; })
+ * // => Echoes `2` then `1`.
+ * </code>
+ */
+function eachRight($collection, callable $iteratee)
+{
+    $values = \is_object($collection) ? \get_object_vars($collection) : $collection;
+
+    foreach (\array_reverse($values, true) as $index => $value) {
+        if (false === $iteratee($value, $index, $collection)) {
+            break;
+        }
+    }
+
+    return $collection;
+}
diff --git a/src/Collection/every.php b/src/Collection/every.php
new file mode 100644
index 0000000..6ee989a
--- /dev/null
+++ b/src/Collection/every.php
@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * Checks if `predicate` returns truthy for **all** elements of `array`.
+ * Iteration is stopped once `predicate` returns falsey. The predicate is
+ * invoked with three arguments: (value, index, array).
+ *
+ * **Note:** This method returns `true` for
+ * [empty arrays](https://en.wikipedia.org/wiki/Empty_set) because
+ * [everything is true](https://en.wikipedia.org/wiki/Vacuous_truth) of
+ * elements of empty arrays.
+ *
+ * @category Array
+ *
+ * @param iterable $collection The array to iterate over.
+ * @param callable $predicate  The function invoked per iteration.
+ *
+ * @return bool `true` if all elements pass the predicate check, else `false`.
+ * @example
+ * <code>
+ * every([true, 1, null, 'yes'], function ($value) { return is_bool($value);})
+ * // => false
+ *
+ * $users = [
+ *     ['user' => 'barney', 'age' => 36, 'active' => false],
+ *     ['user' => 'fred', 'age' => 40, 'active' => false],
+ * ];
+ *
+ * // The `matches` iteratee shorthand.
+ * $this->assertFalse(every($users, ['user' => 'barney', 'active' => false]));
+ * // false
+ *
+ * // The `matchesProperty` iteratee shorthand.
+ * $this->assertTrue(every($users, ['active', false]));
+ * // true
+ *
+ * // The `property` iteratee shorthand.
+ * $this->assertFalse(every($users, 'active'));
+ * //false
+ *
+ * </code>
+ */
+function every(iterable $collection, $predicate): bool
+{
+    $iteratee = baseIteratee($predicate);
+
+    foreach ($collection as $key => $value) {
+        if (!$iteratee($value, $key, $collection)) {
+            return false;
+        }
+    }
+
+    return true;
+}
diff --git a/src/Collection/filter.php b/src/Collection/filter.php
new file mode 100644
index 0000000..3c3b9bf
--- /dev/null
+++ b/src/Collection/filter.php
@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * Iterates over elements of `array`, returning an array of all elements
+ * `predicate` returns truthy for. The predicate is invoked with three
+ * arguments: (value, index, array).
+ *
+ * **Note:** Unlike `remove`, this method returns a new array.
+ *
+ * @category Collection
+ *
+ * @param iterable $array     The array to iterate over.
+ * @param callable $predicate The function invoked per iteration.
+ *
+ * @return array the new filtered array.
+ *
+ * @example
+ * <code>
+ * $users = [
+ *     [ 'user' => 'barney', 'age' => 36, 'active' => true],
+ *     [ 'user' => 'fred',   'age' => 40, 'active' => false]
+ * ];
+ *
+ * filter($users, function($o) { return !$o['active']; });
+ * // => objects for ['fred']
+ *
+ * // The `matches` iteratee shorthand.
+ * filter($users, ['age' => 36, 'active' => true]);
+ * // => objects for ['barney']
+ *
+ * // The `matchesProperty` iteratee shorthand.
+ * filter($users, ['active', false]);
+ * // => objects for ['fred']
+ *
+ * // The `property` iteratee shorthand.
+ * filter($users, 'active');
+ * // => objects for ['barney']
+ * </code>
+ */
+function filter(iterable $array, $predicate = null): array
+{
+    $iteratee = baseIteratee($predicate);
+
+    $result = \array_filter(
+        \is_array($array) ? $array : \iterator_to_array($array),
+        function ($value, $key) use ($array, $iteratee) {
+            return $iteratee($value, $key, $array);
+        },
+        \ARRAY_FILTER_USE_BOTH
+    );
+
+    return \array_values($result);
+}
diff --git a/src/Collection/find.php b/src/Collection/find.php
new file mode 100644
index 0000000..e38807f
--- /dev/null
+++ b/src/Collection/find.php
@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * Iterates over elements of `collection`, returning the first element
+ * `predicate` returns truthy for. The predicate is invoked with three
+ * arguments: (value, index|key, collection).
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to inspect.
+ * @param callable $predicate  The function invoked per iteration.
+ * @param int      $fromIndex  The index to search from.
+ *
+ * @return mixed Returns the matched element, else `null`.
+ *
+ * @example
+ * <code>
+ * $users = [
+ *     ['user' => 'barney',  'age' => 36, 'active' => true],
+ *     ['user' => 'fred',    'age' => 40, 'active' => false],
+ *     ['user' => 'pebbles', 'age' => 1,  'active' => true]
+ * ];
+ *
+ * find($users, function($o) { return $o['age'] < 40; });
+ * // => object for 'barney'
+ *
+ * // The `matches` iteratee shorthand.
+ * find($users, ['age' => 1, 'active' => true]);
+ * // => object for 'pebbles'
+ *
+ * // The `matchesProperty` iteratee shorthand.
+ * find($users, ['active', false]);
+ * // => object for 'fred'
+ *
+ * // The `property` iteratee shorthand.
+ * find($users, 'active');
+ * // => object for 'barney'
+ * </code>
+ */
+function find(iterable $collection, $predicate = null, int $fromIndex = 0)
+{
+    $iteratee = baseIteratee($predicate);
+
+    foreach (\array_slice(\is_array($collection) ? $collection : \iterator_to_array($collection), $fromIndex) as $key => $value) {
+        if ($iteratee($value, $key, $collection)) {
+            return $value;
+        }
+    }
+
+    return null;
+}
diff --git a/src/Collection/findLast.php b/src/Collection/findLast.php
new file mode 100644
index 0000000..2e7cb05
--- /dev/null
+++ b/src/Collection/findLast.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * This method is like `find` except that it iterates over elements of
+ * `collection` from right to left.
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to inspect.
+ * @param callable $predicate  The function invoked per iteration.
+ * @param int      $fromIndex  The index to search from.
+ *
+ * @return mixed Returns the matched element, else `undefined`.
+ *
+ * @example
+ * <code>
+ * findLast([1, 2, 3, 4], function ($n) { return $n % 2 == 1; })
+ * // => 3
+ * </code>
+ */
+function findLast(iterable $collection, $predicate = null, int $fromIndex = 0)
+{
+    $iteratee = baseIteratee($predicate);
+
+    foreach (\array_slice(\array_reverse(\is_array($collection) ? $collection : \iterator_to_array($collection), true), $fromIndex) as $key => $value) {
+        if ($iteratee($value, $key, $collection)) {
+            return $value;
+        }
+    }
+
+    return null;
+}
diff --git a/src/Collection/flatMap.php b/src/Collection/flatMap.php
new file mode 100644
index 0000000..889cead
--- /dev/null
+++ b/src/Collection/flatMap.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseFlatten;
+
+/**
+ * Creates a flattened array of values by running each element in `collection`
+ * through `iteratee` and flattening the mapped results. The iteratee is invoked
+ * with three arguments: (value, index|key, collection).
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to iterate over.
+ * @param callable $iteratee The function invoked per iteration.
+ *
+ * @return array the new flattened array.
+ *
+ * @example
+ * <code>
+ * function duplicate($n) {
+ *   return [$n, $n]
+ * }
+ *
+ * flatMap([1, 2], 'duplicate')
+ * // => [1, 1, 2, 2]
+ * </code>
+ */
+function flatMap(iterable $collection, callable $iteratee): array
+{
+    return baseFlatten(map($collection, $iteratee), 1);
+}
diff --git a/src/Collection/flatMapDeep.php b/src/Collection/flatMapDeep.php
new file mode 100644
index 0000000..5c09dd7
--- /dev/null
+++ b/src/Collection/flatMapDeep.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseFlatten;
+
+/**
+ * This method is like `flatMap` except that it recursively flattens the
+ * mapped results.
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to iterate over.
+ * @param callable $iteratee The function invoked per iteration.
+ *
+ * @return array Returns the new flattened array.
+ * @example
+ * <code>
+ * function duplicate($n) {
+ *   return [[[$n, $n]]];
+ * }
+ *
+ * flatMapDeep([1, 2], 'duplicate');
+ * // => [1, 1, 2, 2]
+ * </code>
+ */
+function flatMapDeep(iterable $collection, callable $iteratee): array
+{
+    return baseFlatten(map($collection, $iteratee), \PHP_INT_MAX);
+}
diff --git a/src/Collection/flatMapDepth.php b/src/Collection/flatMapDepth.php
new file mode 100644
index 0000000..4bdd5ad
--- /dev/null
+++ b/src/Collection/flatMapDepth.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseFlatten;
+
+/**
+ * This method is like `flatMap` except that it recursively flattens the
+ * mapped results up to `depth` times.
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to iterate over.
+ * @param callable $iteratee The function invoked per iteration.
+ * @param int      $depth    The maximum recursion depth.
+ *
+ * @return array the new flattened array.
+ * @example
+ * <code>
+ * function duplicate($n) {
+ *   return [[[$n, $n]]]
+ * }
+ *
+ * flatMapDepth([1, 2], 'duplicate', 2)
+ * // => [[1, 1], [2, 2]]
+ * </code>
+ */
+function flatMapDepth(iterable $collection, callable $iteratee, int $depth = 1): array
+{
+    return baseFlatten(map($collection, $iteratee), $depth);
+}
diff --git a/src/Collection/groupBy.php b/src/Collection/groupBy.php
new file mode 100644
index 0000000..2295d56
--- /dev/null
+++ b/src/Collection/groupBy.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\createAggregator;
+
+/**
+ * Creates an array composed of keys generated from the results of running
+ * each element of `collection` through `iteratee`. The order of grouped values
+ * is determined by the order they occur in `collection`. The corresponding
+ * value of each key is an array of elements responsible for generating the
+ * key. The iteratee is invoked with one argument: (value).
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to iterate over.
+ * @param callable $iteratee The iteratee to transform keys.
+ *
+ * @return array Returns the composed aggregate object.
+ * @example
+ * <code>
+ * groupBy([6.1, 4.2, 6.3], 'floor');
+ * // => ['6' => [6.1, 6.3], '4' => [4.2]]
+ *
+ * groupBy(['one', 'two', 'three'], 'strlen');
+ * // => ['3' => ['one', 'two'], '5' => ['three']]
+ * </code>
+ */
+function groupBy(iterable $collection, $iteratee): array
+{
+    return createAggregator(function ($result, $value, $key) {
+        if (!isset($result[$key])) {
+            $result[$key] = [];
+        }
+
+        $result[$key][] = $value;
+
+        return $result;
+    })($collection, $iteratee);
+}
diff --git a/src/Collection/invokeMap.php b/src/Collection/invokeMap.php
new file mode 100644
index 0000000..b5b4ddd
--- /dev/null
+++ b/src/Collection/invokeMap.php
@@ -0,0 +1,51 @@
+<?php
+
+// No 'declare(strict_types=1)' here as the invoked method needs to use weak-type
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseInvoke;
+use function _\internal\baseRest;
+
+/**
+ * Invokes the method at `path` of each element in `collection`, returning
+ * an array of the results of each invoked method. Any additional arguments
+ * are provided to each invoked method. If `path` is a function, it's invoked
+ * for, and `this` bound to, each element in `collection`.
+ *
+ * @category Collection
+ *
+ * @param iterable              $collection The collection to iterate over.
+ * @param array|callable|string $path       The path of the method to invoke or the function invoked per iteration.
+ * @param array                 $args       The arguments to invoke each method with.
+ *
+ * @return array the array of results.
+ * @example
+ * <code>
+ * invokeMap([[5, 1, 7], [3, 2, 1]], function($result) { sort($result); return $result;})
+ * // => [[1, 5, 7], [1, 2, 3]]
+ *
+ * invokeMap([123, 456], 'str_split')
+ * // => [['1', '2', '3'], ['4', '5', '6']]
+ * </code>
+ */
+function invokeMap(iterable $collection, $path, array $args = []): array
+{
+    return baseRest(function ($collection, $path, $args) {
+        $isFunc = \is_callable($path);
+        $result = [];
+
+        each($collection, function ($value) use (&$result, $isFunc, $path, $args) {
+            $result[] = $isFunc ? $path($value, ...$args) : baseInvoke($value, $path, $args);
+        });
+
+        return $result;
+    })($collection, $path, ...$args);
+}
diff --git a/src/Collection/keyBy.php b/src/Collection/keyBy.php
new file mode 100644
index 0000000..229206b
--- /dev/null
+++ b/src/Collection/keyBy.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\createAggregator;
+
+/**
+ * Creates an object composed of keys generated from the results of running
+ * each element of `collection` through `iteratee`. The corresponding value of
+ * each key is the last element responsible for generating the key. The
+ * iteratee is invoked with one argument: (value).
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to iterate over.
+ * @param callable $iteratee   The iteratee to transform keys.
+ *
+ * @return array the composed aggregate object.
+ * @example
+ * <code>
+ * $array = [
+ *   ['direction' => 'left', 'code' => 97],
+ *   ['direction' => 'right', 'code' => 100],
+ * ];
+ *
+ * keyBy($array, function ($o) { return \chr($o['code']); })
+ * // => ['a' => ['direction' => 'left', 'code' => 97], 'd' => ['direction' => 'right', 'code' => 100]]
+ *
+ * keyBy($array, 'direction');
+ * // => ['left' => ['direction' => 'left', 'code' => 97], 'right' => ['direction' => 'right', 'code' => 100]]
+ * </code>
+ */
+function keyBy(iterable $collection, $iteratee): array
+{
+    return createAggregator(function ($result, $value, $key) {
+        $result[$key] = $value;
+
+        return $result;
+    })($collection, $iteratee);
+}
diff --git a/src/Collection/map.php b/src/Collection/map.php
index 3f37f31..5b6fb6c 100644
--- a/src/Collection/map.php
+++ b/src/Collection/map.php
@@ -61,9 +61,9 @@ function map($collection, $iteratee): array
 
     if (\is_array($collection)) {
         $values = $collection;
-    } else if ($collection instanceof \Traversable) {
+    } elseif ($collection instanceof \Traversable) {
         $values = \iterator_to_array($collection);
-    } else if (\is_object($collection)) {
+    } elseif (\is_object($collection)) {
         $values = \get_object_vars($collection);
     }
 
@@ -72,4 +72,4 @@ function map($collection, $iteratee): array
     return \array_map(function ($value, $index) use ($callable, $collection) {
         return $callable($value, $index, $collection);
     }, $values, \array_keys($values));
-}
\ No newline at end of file
+}
diff --git a/src/Collection/orderBy.php b/src/Collection/orderBy.php
new file mode 100644
index 0000000..346fb75
--- /dev/null
+++ b/src/Collection/orderBy.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseOrderBy;
+
+/**
+ * This method is like `sortBy` except that it allows specifying the sort
+ * orders of the iteratees to sort by. If `orders` is unspecified, all values
+ * are sorted in ascending order. Otherwise, specify an order of "desc" for
+ * descending or "asc" for ascending sort order of corresponding values.
+ *
+ * @category Collection
+ *
+ * @param iterable|null               $collection The collection to iterate over.
+ * @param array[]|callable[]|string[] $iteratee   The iteratee(s) to sort by.
+ * @param string[]                    $orders     The sort orders of `iteratees`.
+ *
+ * @return array the new sorted array.
+ * @example
+ * <code>
+ * $users = [
+ *   ['user' => 'fred',   'age' => 48],
+ *   ['user' => 'barney', 'age' => 34],
+ *   ['user' => 'fred',   'age' => 40],
+ *   ['user' => 'barney', 'age' => 36]
+ * ]
+ *
+ * // Sort by `user` in ascending order and by `age` in descending order.
+ * orderBy($users, ['user', 'age'], ['asc', 'desc'])
+ * // => [['user' => 'barney', 'age' => 36], ['user' => 'barney', 'age' => 34], ['user' => 'fred', 'age' => 48], ['user' => 'fred', 'age' => 40]]
+ * </code>
+ */
+function orderBy(?iterable $collection, array $iteratee, array $orders): array
+{
+    if (null === $collection) {
+        return [];
+    }
+
+    return baseOrderBy($collection, $iteratee, $orders);
+}
diff --git a/src/Collection/partition.php b/src/Collection/partition.php
new file mode 100644
index 0000000..ac4eae5
--- /dev/null
+++ b/src/Collection/partition.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\createAggregator;
+
+/**
+ * Creates an array of elements split into two groups, the first of which
+ * contains elements `predicate` returns truthy for, the second of which
+ * contains elements `predicate` returns falsey for. The predicate is
+ * invoked with one argument: (value).
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to iterate over.
+ * @param callable $predicate  The function invoked per iteration.
+ *
+ * @return array the array of grouped elements.
+ * @example
+ * <code>
+ * $users = [
+ *   ['user' => 'barney',  'age' => 36, 'active' => false],
+ *   ['user' => 'fred',    'age' => 40, 'active' => true],
+ *   ['user' => 'pebbles', 'age' => 1,  'active' => false]
+ * ];
+ *
+ * partition($users, function($user) { return $user['active']; })
+ * // => objects for [['fred'], ['barney', 'pebbles']]
+ * </code>
+ */
+function partition(iterable $collection, $predicate = null): array
+{
+    return createAggregator(function ($result, $value, $key) {
+        $result[$key ? 0 : 1][] = $value;
+
+        return $result;
+    }, function () {
+        return [[], []];
+    })($collection, $predicate);
+}
diff --git a/src/Collection/reduce.php b/src/Collection/reduce.php
new file mode 100644
index 0000000..703be86
--- /dev/null
+++ b/src/Collection/reduce.php
@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * Reduces `collection` to a value which is the accumulated result of running
+ * each element in `collection` thru `iteratee`, where each successive
+ * invocation is supplied the return value of the previous. If `accumulator`
+ * is not given, the first element of `collection` is used as the initial
+ * value. The iteratee is invoked with four arguments:
+ * (accumulator, value, index|key, collection).
+ *
+ * Many lodash methods are guarded to work as iteratees for methods like
+ * `reduce`, `reduceRight`, and `transform`.
+ *
+ * The guarded methods are:
+ * `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `orderBy`,
+ * and `sortBy`
+ *
+ * @category Collection
+ *
+ * @param iterable $collection  The collection to iterate over.
+ * @param mixed    $iteratee    The function invoked per iteration.
+ * @param mixed    $accumulator The initial value.
+ *
+ * @return mixed Returns the accumulated value.
+ *
+ * @example
+ * <code>
+ * reduce([1, 2], function($sum, $n) { return $sum + $n; }, 0)
+ * // => 3
+ *
+ * reduce(['a' => 1, 'b' => 2, 'c' => 1], function ($result, $value, $key) {
+ *     if (!isset($result[$value])) {
+ *         $result[$value] = [];
+ *     }
+ *     $result[$value][] = $key;
+ *
+ *     return $result;
+ *  }, [])
+ * // => ['1' => ['a', 'c'], '2' => ['b']] (iteration order is not guaranteed)
+ * </code>
+ */
+function reduce(iterable $collection, $iteratee, $accumulator = null)
+{
+    $func = function (iterable $array, $iteratee, $accumulator, $initAccum = null) {
+        $length = \count(\is_array($array) ? $array : \iterator_to_array($array));
+
+        if ($initAccum && $length) {
+            $accumulator = \current($array);
+        }
+        foreach ($array as $key => $value) {
+            $accumulator = $iteratee($accumulator, $value, $key, $array);
+        }
+
+        return $accumulator;
+    };
+
+    return $func($collection, baseIteratee($iteratee), $accumulator, null === $accumulator);
+}
diff --git a/src/Collection/reduceRight.php b/src/Collection/reduceRight.php
new file mode 100644
index 0000000..8a51c16
--- /dev/null
+++ b/src/Collection/reduceRight.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+use function _\internal\baseReduce;
+
+/**
+ * This method is like `reduce` except that it iterates over elements of
+ * `collection` from right to left.
+ *
+ * @category Collection
+ *
+ * @param iterable $collection  The collection to iterate over.
+ * @param mixed    $iteratee    The function invoked per iteration.
+ * @param mixed    $accumulator The initial value.
+ *
+ * @return mixed Returns the accumulated value.
+ *
+ * @example
+ * <code>
+ * $array = [[0, 1], [2, 3], [4, 5]];
+ *
+ * reduceRight(array, (flattened, other) => flattened.concat(other), [])
+ * // => [4, 5, 2, 3, 0, 1]
+ * </code>
+ */
+function reduceRight(iterable $collection, $iteratee, $accumulator = null)
+{
+    return baseReduce(\array_reverse($collection instanceof \Traversable ? \iterator_to_array($collection, true) : $collection, true), baseIteratee($iteratee), $accumulator, null === $accumulator);
+}
diff --git a/src/Collection/reject.php b/src/Collection/reject.php
new file mode 100644
index 0000000..1a63722
--- /dev/null
+++ b/src/Collection/reject.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * The opposite of `filter` this method returns the elements of `collection`
+ * that `predicate` does **not** return truthy for.
+ *
+ * @category Collection
+ *
+ * @param iterable $collection The collection to iterate over.
+ * @param callable $predicate  The function invoked per iteration.
+ *
+ * @return array the new filtered array.
+ *
+ * @example
+ * <code>
+ * $users = [
+ *   ['user' => 'barney', 'active' => true],
+ *   ['user' => 'fred',   'active' => false]
+ * ]
+ *
+ * reject($users, 'active')
+ * // => objects for ['fred']
+ * </code>
+ */
+function reject(iterable $collection, $predicate = null): array
+{
+    return filter($collection, negate(baseIteratee($predicate)));
+}
diff --git a/src/Collection/sample.php b/src/Collection/sample.php
new file mode 100644
index 0000000..43dec1f
--- /dev/null
+++ b/src/Collection/sample.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Gets a random element from `array`.
+ *
+ * @category Array
+ *
+ * @param array $array The array to sample.
+ *
+ * @return mixed Returns the random element.
+ *
+ * @example
+ * <code>
+ * sample([1, 2, 3, 4])
+ * // => 2
+ * </code>
+ */
+function sample(array $array)
+{
+    /** @var string|int $key */
+    $key = \array_rand($array, 1);
+
+    return $array[$key];
+}
diff --git a/src/Collection/sampleSize.php b/src/Collection/sampleSize.php
new file mode 100644
index 0000000..199842a
--- /dev/null
+++ b/src/Collection/sampleSize.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Gets `n` random elements at unique keys from `array` up to the
+ * size of `array`.
+ *
+ * @category Array
+ *
+ * @param array $array The array to sample.
+ * @param int $n The number of elements to sample.
+ *
+ * @return array the random elements.
+ * @example
+ * <code>
+ * sampleSize([1, 2, 3], 2)
+ * // => [3, 1]
+ *
+ * sampleSize([1, 2, 3], 4)
+ * // => [2, 3, 1]
+ * </code>
+ */
+function sampleSize(array $array, int $n = 1): array
+{
+    $result = [];
+    $count = \count($array);
+
+    foreach ((array) \array_rand($array, $n > $count ? $count : $n) as $index) {
+        $result[] = $array[$index];
+    }
+
+    return $result;
+}
diff --git a/src/Collection/shuffle.php b/src/Collection/shuffle.php
new file mode 100644
index 0000000..5dc4242
--- /dev/null
+++ b/src/Collection/shuffle.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates an array of shuffled values
+ *
+ * @category Array
+ *
+ * @param array $array The array to shuffle.
+ *
+ * @return array the new shuffled array.
+ * @example
+ * <code>
+ * shuffle([1, 2, 3, 4])
+ * // => [4, 1, 3, 2]
+ * </code>
+ */
+function shuffle(array $array = []): array
+{
+    \shuffle($array);
+
+    return $array;
+}
diff --git a/src/Collection/size.php b/src/Collection/size.php
new file mode 100644
index 0000000..5116e9e
--- /dev/null
+++ b/src/Collection/size.php
@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Gets the size of `collection` by returning its length for array
+ * values or the number of public properties for objects.
+ *
+ * @category Collection
+ *
+ * @param array|object|string $collection The collection to inspect.
+ *
+ * @return int Returns the collection size.
+ * @example
+ * <code>
+ * size([1, 2, 3]);
+ * // => 3
+ *
+ * size(new class { public $a = 1; public $b = 2; private $c = 3; });
+ * // => 2
+ *
+ * size('pebbles');
+ * // => 7
+ * </code>
+ */
+function size($collection): int
+{
+    if (\is_string($collection)) {
+        return \strlen($collection);
+    }
+
+    if (\is_array($collection) || $collection instanceof \Countable) {
+        return \count($collection);
+    }
+
+    if ($collection instanceof \Traversable) {
+        return \count(\iterator_to_array($collection));
+    }
+
+    if (\is_object($collection)) {
+        return \count(\get_object_vars($collection));
+    }
+
+    return 0;
+}
diff --git a/src/Collection/some.php b/src/Collection/some.php
new file mode 100644
index 0000000..02d8b9d
--- /dev/null
+++ b/src/Collection/some.php
@@ -0,0 +1,61 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * Checks if `predicate` returns truthy for **any** element of `collection`.
+ * Iteration is stopped once `predicate` returns truthy. The predicate is
+ * invoked with three arguments: (value, index|key, collection).
+ *
+ * @category Collection
+ *
+ * @param iterable              $collection The collection to iterate over.
+ * @param callable|string|array $predicate  The function invoked per iteration.
+ *
+ * @return boolean Returns `true` if any element passes the predicate check, else `false`.
+ * @example
+ * <code>
+ * some([null, 0, 'yes', false], , function ($value) { return \is_bool($value); }));
+ * // => true
+ *
+ * $users = [
+ *   ['user' => 'barney', 'active' => true],
+ *   ['user' => 'fred',   'active' => false]
+ * ];
+ *
+ * // The `matches` iteratee shorthand.
+ * some($users, ['user' => 'barney', 'active' => false ]);
+ * // => false
+ *
+ * // The `matchesProperty` iteratee shorthand.
+ * some($users, ['active', false]);
+ * // => true
+ *
+ * // The `property` iteratee shorthand.
+ * some($users, 'active');
+ * // => true
+ * </code>
+ */
+function some(iterable $collection, $predicate = null): bool
+{
+    $iteratee = baseIteratee($predicate);
+
+    foreach ($collection as $key => $value) {
+        if ($iteratee($value, $key, $collection)) {
+            return true;
+        }
+    }
+
+    return false;
+}
diff --git a/src/Collection/sortBy.php b/src/Collection/sortBy.php
index b87d2b6..0e2e41c 100644
--- a/src/Collection/sortBy.php
+++ b/src/Collection/sortBy.php
@@ -21,8 +21,8 @@
  *
  * @category Collection
  *
- * @param array|object           $collection The collection to iterate over.
- * @param    callable|callable[] $iteratees  The iteratees to sort by.
+ * @param array|object|null   $collection The collection to iterate over.
+ * @param callable|callable[] $iteratees  The iteratees to sort by.
  *
  * @return array Returns the new sorted array.
  * @example
@@ -41,13 +41,13 @@
  * // => [['user' => 'barney', 'age' => 34], ['user' => 'barney', 'age' => 36], ['user' => 'fred', 'age' => 40], ['user' => 'fred', 'age' => 48]]
  * </code>
  */
-function sortBy($collection, $iteratees)
+function sortBy($collection, $iteratees): array
 {
     if (null === $collection) {
         return [];
     };
 
-    if (\is_callable($iteratees)) {
+    if (\is_callable($iteratees) || !\is_iterable($iteratees)) {
         $iteratees = [$iteratees];
     }
 
@@ -58,15 +58,15 @@ function sortBy($collection, $iteratees)
         $iteratees = [$iteratees[0]];
     }*/
 
-    $result = $collection;
+    $result = \is_object($collection) ? \get_object_vars($collection) : $collection;
 
     foreach ($iteratees as $callable) {
         usort($result, function ($a, $b) use ($callable) {
             $iteratee = baseIteratee($callable);
 
-            return $iteratee($a) <=> $iteratee($b);
+            return $iteratee($a, $b) <=> $iteratee($b, $a);
         });
     }
 
     return $result;
-}
\ No newline at end of file
+}
diff --git a/src/Date/now.php b/src/Date/now.php
index 7e536e8..d619283 100644
--- a/src/Date/now.php
+++ b/src/Date/now.php
@@ -27,4 +27,4 @@
 function now(): int
 {
     return (int) (\microtime(true) * 1000);
-}
\ No newline at end of file
+}
diff --git a/src/Function/after.php b/src/Function/after.php
new file mode 100644
index 0000000..6a972c1
--- /dev/null
+++ b/src/Function/after.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * The opposite of `before`; this method creates a function that invokes
+ * `func` once it's called `n` or more times.
+ *
+ * @category Function
+ *
+ * @param int      $n    The number of calls before `func` is invoked.
+ * @param Callable $func The function to restrict.
+ *
+ * @return Callable Returns the new restricted function.
+ *
+ * @example
+ * <code>
+ * $saves = ['profile', 'settings'];
+ *
+ * $done = after(count($saves), function() {
+ *   echo 'done saving!';
+ * });
+ *
+ * forEach($saves, function($type) use($done) {
+ *   asyncSave([ 'type' => $type, 'complete' => $done ]);
+ * });
+ * // => Prints 'done saving!' after the two async saves have completed.
+ * </code>
+ */
+function after(int $n, callable $func): callable
+{
+    return function (...$args) use (&$n, $func) {
+        if (--$n < 1) {
+            return $func(...$args);
+        }
+    };
+}
diff --git a/src/Function/ary.php b/src/Function/ary.php
new file mode 100644
index 0000000..47d5436
--- /dev/null
+++ b/src/Function/ary.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a function that invokes `func`, with up to `n` arguments,
+ * ignoring any additional arguments.
+ *
+ * @category Function
+ *
+ * @param callable $func The function to cap arguments for.
+ * @param int      $n    The arity cap.
+ *
+ * @return Callable Returns the new capped function.
+ *
+ * @example
+ * <code>
+ * map(['6', '8', '10'], ary('intval', 1));
+ * // => [6, 8, 10]
+ * </code>
+ */
+function ary(callable $func, int $n): callable
+{
+    return function (...$args) use ($func, $n) {
+        \array_splice($args, $n);
+
+        return $func(...$args);
+    };
+}
diff --git a/src/Function/before.php b/src/Function/before.php
new file mode 100644
index 0000000..1dcacd4
--- /dev/null
+++ b/src/Function/before.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a function that invokes `func`, with the arguments
+ * of the created function, while it's called less than `n` times. Subsequent
+ * calls to the created function return the result of the last `func` invocation.
+ *
+ * @category Function
+ *
+ * @param int      $n    The number of calls at which `func` is no longer invoked.
+ * @param callable $func The function to restrict.
+ *
+ * @return callable Returns the new restricted function.
+ *
+ * @example
+ * <code>
+ * $users = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+ * $result = uniqBy(map($users, before(5, [$repository, 'find'])), 'id')
+ * // => Fetch up to 4 results.
+ * </code>
+ */
+function before(int $n, callable $func): callable
+{
+    $result = null;
+
+    return function (...$args) use (&$result, &$n, &$func) {
+        if (--$n > 0) {
+            $result = $func(...$args);
+        }
+
+        return $result;
+    };
+}
diff --git a/src/Function/bind.php b/src/Function/bind.php
new file mode 100644
index 0000000..e69e0bd
--- /dev/null
+++ b/src/Function/bind.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a function that invokes `func` with the `this` binding of `object`
+ * and `partials` prepended to the arguments it receives.
+ *
+ * @category Function
+ *
+ * @param callable          $function The function to bind.
+ * @param object|mixed      $object   The `object` binding of `func`.
+ * @param array<int, mixed> $partials The arguments to be partially applied.
+ *
+ * @return callable Returns the new bound function.
+ * @example
+ * <code>
+ * function greet($greeting, $punctuation) {
+ *   return $greeting . ' ' . $this->user . $punctuation;
+ * }
+ *
+ * $object = $object = new class {
+ *     public $user = 'fred';
+ * };
+ *
+ * $bound = bind('greet', $object, 'hi');
+ * $bound('!');
+ * // => 'hi fred!'
+ * </code>
+ */
+function bind(callable $function, $object, ...$partials): callable
+{
+    return function (...$args) use ($object, $function, $partials) {
+        $function = \Closure::fromCallable($function)->bindTo($object, $function instanceof \Closure ? $object : null);
+
+        return $function(...array_merge($partials, $args));
+    };
+}
diff --git a/src/Function/bindKey.php b/src/Function/bindKey.php
new file mode 100644
index 0000000..636cec6
--- /dev/null
+++ b/src/Function/bindKey.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a function that invokes the method `$function` of `$object` with `$partials`
+ * prepended to the arguments it receives.
+ *
+ * This method differs from `bind` by allowing bound functions to reference
+ * methods that may be redefined or don't yet exist
+ *
+ * @category Function
+ *
+ * @param object            $object   The object to invoke the method on.
+ * @param string            $function The name of the method.
+ * @param array<int, mixed> $partials The arguments to be partially applied.
+ *
+ * @return callable Returns the new bound function.
+ * @example
+ * <code>
+ * $object = new class {
+ *     private $user = 'fred';
+ *     function greet($greeting, $punctuation) {
+ *         return $greeting.' '.$this->user.$punctuation;
+ *     }
+ * };
+ *
+ * $bound = bindKey($object, 'greet', 'hi');
+ * $bound('!');
+ * // => 'hi fred!'
+ * </code>
+ */
+function bindKey($object, string $function, ...$partials): callable
+{
+    return function (...$args) use ($object, $function, $partials) {
+        $function = \Closure::fromCallable([$object, $function])->bindTo($object, get_class($object));
+
+        return $function(...array_merge($partials, $args));
+    };
+}
diff --git a/src/Function/curry.php b/src/Function/curry.php
new file mode 100644
index 0000000..d4cdd1c
--- /dev/null
+++ b/src/Function/curry.php
@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a function that accepts arguments of `func` and either invokes
+ * `func` returning its result, if at least `arity` number of arguments have
+ * been provided, or returns a function that accepts the remaining `func`
+ * arguments, and so on. The arity of `func` may be specified if `func.length`
+ * is not sufficient.
+ *
+ * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
+ * may be used as a placeholder for provided arguments.
+ *
+ * **Note:** This method doesn't set the "length" property of curried functions.
+ *
+ * @category Function
+ *
+ * @param callable $func  The function to curry.
+ * @param int|null $arity The arity of `func`.
+ *
+ * @return callable Returns the new curried function.
+ * @example
+ * <code>
+ * $abc = function($a, $b, $c) {
+ *   return [$a, $b, $c];
+ * };
+ *
+ * $curried = curry($abc);
+ *
+ * $curried(1)(2)(3);
+ * // => [1, 2, 3]
+ *
+ * $curried(1, 2)(3);
+ * // => [1, 2, 3]
+ *
+ * $curried(1, 2, 3);
+ * // => [1, 2, 3]
+ *
+ * // Curried with placeholders.
+ * $curried(1)(_, 3)(2);
+ * // => [1, 2, 3]
+ * </code>
+ */
+function curry(callable $func, ?int $arity = null)
+{
+    $curry = function ($arguments) use ($func, &$curry, $arity) {
+        $requiredArguments = (new \ReflectionFunction($func))->getNumberOfParameters();
+        $arity = $arity ?? $requiredArguments;
+
+        return function (...$args) use ($func, $arguments, $curry, $arity) {
+            if (false !== \array_search(_, $arguments)) {
+                foreach ($arguments as $i => $argument) {
+                    if (_ !== $argument) {
+                        continue;
+                    }
+
+                    $arguments[$i] = current($args);
+                    next($args);
+                }
+            } else {
+                $arguments = \array_merge($arguments, $args);
+            }
+
+            if ($arity <= \count(\array_filter($arguments, function ($value) {
+                return _ !== $value;
+            }))) {
+                return $func(...$arguments);
+            }
+
+            return $curry($arguments);
+        };
+    };
+
+    return $curry([]);
+}
diff --git a/src/Function/delay.php b/src/Function/delay.php
new file mode 100644
index 0000000..53418fe
--- /dev/null
+++ b/src/Function/delay.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Invokes `func` after `wait` milliseconds. Any additional arguments are
+ * provided to `func` when it's invoked.
+ *
+ * @category Function
+ *
+ * @param callable          $func The function to delay.
+ * @param int               $wait The number of milliseconds to delay invocation.
+ * @param array<int, mixed> $args
+ *
+ * @return int the timer id.
+ * @example
+ * <code>
+ * delay(function($text) {
+ *   echo $text;
+ * }, 1000, 'later');
+ * // => Echo 'later' after one second.
+ * </code>
+ */
+function delay(callable $func, int $wait = 1, ...$args): int
+{
+    usleep($wait * 1000);
+
+    $func(...$args);
+
+    return 1;
+}
diff --git a/src/Function/flip.php b/src/Function/flip.php
new file mode 100644
index 0000000..91c1e33
--- /dev/null
+++ b/src/Function/flip.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseRest;
+use function _\internal\castSlice;
+
+/**
+ * Creates a function that invokes `func` with arguments reversed.
+ *
+ * @category Function
+ *
+ * @param callable $func The function to flip arguments for.
+ *
+ * @return callable Returns the new flipped function.
+ *
+ * @example
+ * <code>
+ * $flipped = flip(function() {
+ *   return func_get_args();
+ * });
+ *
+ * flipped('a', 'b', 'c', 'd');
+ * // => ['d', 'c', 'b', 'a']
+ * </code>
+ */
+function flip(callable $func): callable
+{
+    return function (...$values) use ($func) {
+        return \array_reverse($func(...$values), false);
+    };
+}
diff --git a/src/Function/memoize.php b/src/Function/memoize.php
new file mode 100644
index 0000000..13ec3a1
--- /dev/null
+++ b/src/Function/memoize.php
@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+/**
+ * Creates a function that memoizes the result of `func`. If `resolver` is
+ * provided, it determines the cache key for storing the result based on the
+ * arguments provided to the memoized function. By default, the first argument
+ * provided to the memoized function is used as the map cache key
+ *
+ * **Note:** The cache is exposed as the `cache` property on the memoized
+ * function. Its creation may be customized by replacing the `_.memoize.Cache`
+ * constructor with one whose instances implement the
+ * [`Map`](http://ecma-international.org/ecma-262/7.0/#sec-properties-of-the-map-prototype-object)
+ * method interface of `clear`, `delete`, `get`, `has`, and `set`.
+ *
+ * @category Function
+ *
+ * @param callable      $func     The function to have its output memoized.
+ * @param callable|null $resolver The function to resolve the cache key.
+ *
+ * @return callable Returns the new memoized function.
+ *
+ * @example
+ * <code>
+ * $object = ['a' => 1, 'b' => 2];
+ * $other = ['c' => 3, 'd' => 4];
+ *
+ * $values = memoize('_\values');
+ * $values($object);
+ * // => [1, 2]
+ *
+ * $values($other);
+ * // => [3, 4]
+ *
+ * $object['a'] = 2;
+ * $values($object);
+ * // => [1, 2]
+ *
+ * // Modify the result cache.
+ * $values->cache->set($object, ['a', 'b']);
+ * $values($object);
+ * // => ['a', 'b']
+ * </code>
+ */
+function memoize(callable $func, callable $resolver = null)
+{
+    $memoized = new class($func, $resolver ?? null) {
+
+        /**
+         * @var CacheInterface
+         */
+        public $cache;
+
+        private $resolver;
+
+        private $func;
+
+        public function __construct(callable $func, ?callable $resolver)
+        {
+            $this->resolver = $resolver;
+            $this->func = $func;
+        }
+
+        public function __invoke()
+        {
+            $args = \func_get_args();
+
+            if ($this->resolver) {
+                $key = \Closure::fromCallable($this->resolver)->bindTo($this)(...$args);
+            } else {
+                $key = &$args[0];
+            }
+
+            $cache = $this->cache;
+
+            if ($cache->has($key)) {
+                return $cache->get($key);
+            }
+
+            $result = ($this->func)(...$args);
+            $this->cache = $this->cache->set($key, $result);
+
+            return $result;
+        }
+    };
+
+    $memoized->cache = new MapCache;
+
+    return $memoized;
+}
diff --git a/src/Function/negate.php b/src/Function/negate.php
new file mode 100644
index 0000000..4032304
--- /dev/null
+++ b/src/Function/negate.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+/**
+ * Creates a function that negates the result of the predicate `func`
+ *
+ * @category Function
+ *
+ * @param callable $predicate The predicate to negate.
+ *
+ * @return callable Returns the new negated function.
+ *
+ * @example
+ * <code>
+ * function isEven($n) {
+ *   return $n % 2 == 0;
+ * }
+ *
+ * filter([1, 2, 3, 4, 5, 6], negate($isEven));
+ * // => [1, 3, 5]
+ * </code>
+ */
+
+function negate(callable $predicate): callable
+{
+    return function () use ($predicate) {
+        return !$predicate(...\func_get_args());
+    };
+}
diff --git a/src/Function/once.php b/src/Function/once.php
new file mode 100644
index 0000000..2ff0909
--- /dev/null
+++ b/src/Function/once.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a function that is restricted to invoking `func` once. Repeat calls
+ * to the function return the value of the first invocation. The `func` is
+ * invoked with the arguments of the created function.
+ *
+ * @category Function
+ *
+ * @param callable $func The function to restrict.
+ *
+ * @return callable the new restricted function.
+ *
+ * @example
+ * <code>
+ * $initialize = once('createApplication');
+ * $initialize();
+ * $initialize();
+ * // => `createApplication` is invoked once
+ * </code>
+ */
+function once(callable $func): callable
+{
+    return before(2, $func);
+}
diff --git a/src/Function/overArgs.php b/src/Function/overArgs.php
new file mode 100644
index 0000000..386c27e
--- /dev/null
+++ b/src/Function/overArgs.php
@@ -0,0 +1,72 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\arrayMap;
+use function _\internal\baseFlatten;
+use function _\internal\baseRest;
+use function _\internal\baseUnary;
+
+/**
+ * Creates a function that invokes `func` with its arguments transformed.
+ *
+ * @static
+ * @memberOf _
+ * @category Function
+ *
+ * @param callable   $func       The function to wrap.
+ * @param callable[] $transforms The argument transforms.
+ *
+ * @return callable the new function.
+ *
+ * @example
+ * <code>
+ * function doubled($n) {
+ *   return $n * 2;
+ * }
+ *
+ * function square($n) {
+ *   return $n * $n;
+ * }
+ *
+ * $func = overArgs(function($x, $y) {
+ *   return [$x, $y];
+ * }, ['square', 'doubled']);
+ *
+ * $func(9, 3);
+ * // => [81, 6]
+ *
+ * $func(10, 5);
+ * // => [100, 10]
+ * </code>
+ */
+function overArgs(callable $func, array $transforms): callable
+{
+    return baseRest(function ($func, $transforms) {
+        $transforms = (\count($transforms) == 1 && \is_array($transforms[0]))
+            ? arrayMap($transforms[0], baseUnary('\_\internal\baseIteratee'))
+            : arrayMap(baseFlatten($transforms, 1), baseUnary('\_\internal\baseIteratee'));
+
+        $funcsLength = \count($transforms);
+
+        return baseRest(function ($args) use ($funcsLength, $transforms, $func) {
+            $index = -1;
+            $length = \min(\count($args), $funcsLength);
+
+            while (++$index < $length) {
+                $args[$index] = $transforms[$index]($args[$index]);
+            }
+
+            return $func(...$args);
+        });
+    })($func, $transforms);
+}
diff --git a/src/Function/partial.php b/src/Function/partial.php
new file mode 100644
index 0000000..8ada3d7
--- /dev/null
+++ b/src/Function/partial.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseRest;
+use function _\internal\shortOut;
+
+/**
+ * Creates a function that invokes `func` with `partials` prepended to the
+ * arguments it receives.
+ *
+ * @category Function
+ *
+ * @param callable          $func     The function to partially apply arguments to.
+ * @param array<int, mixed> $partials The arguments to be partially applied.
+ *
+ * @return callable Returns the new partially applied function.
+ *
+ * @example
+ * <code>
+ * function greet($greeting, $name) {
+ *   return $greeting . ' ' . $name;
+ * }
+ *
+ * $sayHelloTo = partial('greet', 'hello');
+ * $sayHelloTo('fred');
+ * // => 'hello fred'
+ * </code>
+ */
+function partial(callable $func, ...$partials): callable
+{
+    return baseRest(function ($func, $partials) {
+        $wrapper = function () use ($func, $partials) {
+            $arguments = \func_get_args();
+            $argsIndex = -1;
+            $argsLength = \func_num_args();
+            $leftIndex = -1;
+            $leftLength = \count($partials);
+            $args = [];
+
+            while (++$leftIndex < $leftLength) {
+                $args[$leftIndex] = $partials[$leftIndex];
+            }
+            while ($argsLength--) {
+                $args[$leftIndex++] = $arguments[++$argsIndex];
+            }
+
+            return $func(...$args);
+        };
+
+        return shortOut($wrapper);
+    })($func, ...$partials);
+}
diff --git a/src/Function/rest.php b/src/Function/rest.php
new file mode 100644
index 0000000..1402941
--- /dev/null
+++ b/src/Function/rest.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseRest;
+
+/**
+ * Creates a function that invokes `func` with the `this` binding of the
+ * created function and arguments from `start` and beyond provided as
+ * an array.
+ *
+ * @category Function
+ *
+ * @param callable $func  The function to apply a rest parameter to.
+ * @param int|null   $start The start position of the rest parameter.
+ *
+ * @return callable Returns the new function.
+ *
+ * @example
+ * <code>
+ * $say = rest(function($what, $names) {
+ *   return $what . ' ' . implode(', ', initial($names)) .
+ *     (size($names) > 1 ? ', & ' : '') . last($names);
+ * });
+ *
+ * $say('hello', 'fred', 'barney', 'pebbles');
+ * // => 'hello fred, barney, & pebbles'
+ * </code>
+ */
+function rest(callable $func, ?int $start = null): callable
+{
+    return baseRest($func, $start);
+}
diff --git a/src/Function/spread.php b/src/Function/spread.php
new file mode 100644
index 0000000..7dfab5f
--- /dev/null
+++ b/src/Function/spread.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\baseRest;
+use function _\internal\castSlice;
+
+/**
+ * Creates a function that invokes `func` with the `this` binding of the
+ * create function and an array of arguments much like
+ * [`Function#apply`](http://www.ecma-international.org/ecma-262/7.0/#sec-function.prototype.apply).
+ *
+ * **Note:** This method is based on the
+ * [spread operator](https://mdn.io/spread_operator).
+ *
+ * @static
+ * @memberOf _
+ * @since    3.2.0
+ * @category Function
+ *
+ * @param callable $func The function to spread arguments over.
+ * @param int $start The start position of the spread.
+ *
+ * @return callable Returns the new function.
+ *
+ * @example
+ * <code>
+ * $say = spread(function($who, $what) {
+ *   return $who . ' says ' . $what;
+ * });
+ *
+ * $say(['fred', 'hello']);
+ * // => 'fred says hello'
+ * </code>
+ */
+function spread(callable $func, ?int $start = null)
+{
+    $start = null === $start ? 0 : \max($start, 0);
+
+    return baseRest(function ($args) use ($start, $func) {
+        $array = $args[$start];
+        $otherArgs = castSlice($args, 0, $start);
+
+        if ($array) {
+            $otherArgs = \array_merge($otherArgs, $array);
+        }
+
+        return $func(...$otherArgs);
+    });
+}
diff --git a/src/Function/unary.php b/src/Function/unary.php
new file mode 100644
index 0000000..d179ba8
--- /dev/null
+++ b/src/Function/unary.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a function that accepts up to one argument, ignoring any
+ * additional arguments.
+ *
+ * @category Function
+ *
+ * @param callable $func The function to cap arguments for.
+ *
+ * @return callable the new capped function.
+ * @example
+ * <code>
+ * map(['6', '8', '10'], unary('intval'));
+ * // => [6, 8, 10]
+ * </code>
+ */
+function unary(callable $func): callable
+{
+    return ary($func, 1);
+}
diff --git a/src/Function/wrap.php b/src/Function/wrap.php
new file mode 100644
index 0000000..84df495
--- /dev/null
+++ b/src/Function/wrap.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a function that provides `value` to `wrapper` as its first
+ * argument. Any additional arguments provided to the function are appended
+ * to those provided to the `wrapper`.
+ *
+ * @category Function
+ *
+ * @param mixed    $value   The value to wrap.
+ * @param callable $wrapper The wrapper function.
+ *
+ * @return callable the new function.
+ * @example
+ * <code>
+ * $p = wrap('_\escape', function($func, $text) {
+ *     return '<p>' . $func($text) . '</p>';
+ * });
+ *
+ * $p('fred, barney, & pebbles');
+ * // => '<p>fred, barney, &amp; pebbles</p>'
+ * </code>
+ */
+function wrap($value, callable $wrapper = null): callable
+{
+    return partial($wrapper ?? '\_\identity', $value);
+}
diff --git a/src/Hash.php b/src/Hash.php
new file mode 100644
index 0000000..365b8f8
--- /dev/null
+++ b/src/Hash.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+use _\internal\Traits\CacheDataTrait;
+
+final class Hash implements CacheInterface
+{
+    use CacheDataTrait;
+
+    public function __construct()
+    {
+        $this->clear();
+    }
+
+    public function set($key, $value): CacheInterface
+    {
+        $this->size += $this->has($key) ? 0 : 1;
+        $this->__data__[$key] = $value;
+
+        return $this;
+    }
+
+    public function get($key)
+    {
+        return $this->__data__[$key] ?? null;
+    }
+
+    public function has($key): bool
+    {
+        return \array_key_exists($key, $this->__data__);
+    }
+
+    public function clear()
+    {
+        $this->__data__ = [];
+        $this->size = 0;
+    }
+
+    public function delete($key)
+    {
+        $result = $this->has($key);
+
+        unset($this->__data__[$key]);
+
+        $this->size -= $result ? 1 : 0;
+
+        return $result;
+    }
+}
diff --git a/src/Lang/eq.php b/src/Lang/eq.php
new file mode 100644
index 0000000..4f1a280
--- /dev/null
+++ b/src/Lang/eq.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+/**
+ * Performs a comparison between two values to determine if they are equivalent.
+ *
+ * @param mixed $value The value to compare.
+ * @param mixed $other The other value to compare.
+ *
+ * @category Lang
+ *
+ * @return boolean Returns `true` if the values are equivalent, else `false`.
+ * @example
+ * <code>
+ * $object = (object) ['a' => 1];
+ * $other = (object) ['a' => 1];
+ *
+ * eq($object, $object);
+ * // => true
+ *
+ * eq($object, $other);
+ * // => false
+ *
+ * eq('a', 'a');
+ * // => true
+ *
+ * eq(['a'], (object) ['a']);
+ * // => false
+ *
+ * eq(INF, INF);
+ * // => true
+ * </code>
+ */
+function eq($value, $other): bool
+{
+    return $value === $other;
+}
diff --git a/src/Lang/isEqual.php b/src/Lang/isEqual.php
index 2d32001..a0c210b 100644
--- a/src/Lang/isEqual.php
+++ b/src/Lang/isEqual.php
@@ -55,4 +55,4 @@ function isEqual($value, $other): bool
     } catch (ComparisonFailure $failure) {
         return false;
     }
-}
\ No newline at end of file
+}
diff --git a/src/Lang/isError.php b/src/Lang/isError.php
index 9f46150..0a9598f 100644
--- a/src/Lang/isError.php
+++ b/src/Lang/isError.php
@@ -27,6 +27,7 @@
  *
  * isError(\Exception::Class)
  * // => false
+ * </code>
  */
 function isError($value): bool
 {
@@ -35,4 +36,4 @@ function isError($value): bool
     }
 
     return $value instanceof \ParseError || $value instanceof \Error || $value instanceof \Throwable || $value instanceof \SoapFault || $value instanceof \DOMException || $value instanceof \PDOException;
-}
\ No newline at end of file
+}
diff --git a/src/ListCache.php b/src/ListCache.php
new file mode 100644
index 0000000..0c8931d
--- /dev/null
+++ b/src/ListCache.php
@@ -0,0 +1,86 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+use _\internal\Traits\CacheDataTrait;
+use function _\internal\assocIndexOf;
+
+/**
+ * @property array $__data__
+ * @property int   $size
+ */
+final class ListCache implements CacheInterface
+{
+    use CacheDataTrait;
+
+    public function __construct(iterable $entries = null)
+    {
+        $this->clear();
+
+        if (null !== $entries) {
+            foreach ($entries as $key => $entry) {
+                $this->set($key, $entry);
+            }
+        }
+    }
+
+    final public function set($key, $value): CacheInterface
+    {
+        $index = assocIndexOf($this->__data__, $key);
+
+        if ($index < 0) {
+            ++$this->size;
+            $this->__data__[] = [$key, $value];
+        } else {
+            $this->__data__[$index][1] = $value;
+        }
+
+        return $this;
+    }
+
+    final public function get($key)
+    {
+        $index = assocIndexOf($this->__data__, $key);
+
+        return $index < 0 ? null : $this->__data__[$index][1];
+    }
+
+    final public function has($key): bool
+    {
+        return assocIndexOf($this->__data__, $key) > -1;
+    }
+
+    final public function clear()
+    {
+        $this->__data__ = [];
+        $this->size = 0;
+    }
+
+    final public function delete($key)
+    {
+        $index = assocIndexOf($this->__data__, $key);
+
+        if ($index < 0) {
+            return false;
+        }
+
+        $lastIndex = \count($this->__data__) - 1;
+        if ($index === $lastIndex) {
+            \array_pop($this->__data__);
+        } else {
+            \array_splice($this->__data__, $index, 1);
+        }
+        --$this->size;
+
+        return true;
+    }
+}
diff --git a/src/Lodash.php b/src/Lodash.php
index cf7a1cc..08a6e01 100644
--- a/src/Lodash.php
+++ b/src/Lodash.php
@@ -11,6 +11,8 @@
 
 final class _
 {
+    public $__chain__ = false;
+
     public const reInterpolate = '<%=([\s\S]+?)%>';
     public const reEvaluate = "<%([\s\S]+?)%>";
     public const reEscape = "<%-([\s\S]+?)%>";
@@ -44,6 +46,13 @@ final class _
         ],
     ];
 
+    private $value;
+
+    public function __construct($value)
+    {
+        $this->value = $value;
+    }
+
     /**
      * @param string $method
      * @param array  $args
@@ -53,6 +62,40 @@ final class _
      */
     public static function __callStatic(string $method, array $args)
     {
+        if (!\is_callable("_\\$method")) {
+            throw new \InvalidArgumentException("Function _::$method is not valid");
+        }
+
         return ("_\\$method")(...$args);
     }
-}
\ No newline at end of file
+
+    public function __call($method, $arguments)
+    {
+        $this->value = self::__callStatic($method, \array_merge([$this->value], $arguments));
+
+        return $this;
+    }
+
+    public function value()
+    {
+        return $this->value;
+    }
+}
+
+function lodash($value): _
+{
+    return new _($value);
+}
+
+// We can't use "_" as a function name, since it collides with the "_" function in the gettext extension
+// Laravel uses a function __, so only register the alias if the function name is not in use
+if (!function_exists('__')) {
+    function __($value): _
+    {
+        return new _($value);
+    }
+}
+
+if (!defined('_')) {
+    define('_', _::class);
+}
diff --git a/src/MapCache.php b/src/MapCache.php
new file mode 100644
index 0000000..7726fad
--- /dev/null
+++ b/src/MapCache.php
@@ -0,0 +1,87 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+use _\internal\Traits\CacheDataTrait;
+
+/**
+ * @property array $__data__
+ * @property int   $size
+ */
+final class MapCache implements CacheInterface
+{
+    use CacheDataTrait;
+
+    public function __construct(iterable $entries = null)
+    {
+        $this->clear();
+
+        if (null !== $entries) {
+            foreach ($entries as $key => $entry) {
+                $this->set($key, $entry);
+            }
+        }
+    }
+
+    final public function set($key, $value): CacheInterface
+    {
+        $data = $this->getMapData($key);
+        $size = $data->getSize();
+
+        $data->set($key, $value);
+        $this->size += $data->getSize() === $size ? 0 : 1;
+
+        return $this;
+    }
+
+    final public function get($key)
+    {
+        return $this->getMapData($key)->get($key);
+    }
+
+    final public function has($key): bool
+    {
+        return $this->getMapData($key)->has($key);
+    }
+
+    final public function clear()
+    {
+        $this->size = 0;
+        $this->__data__ = [
+            'hash' => new Hash,
+            'map' => new ListCache,
+            'string' => new Hash,
+        ];
+    }
+
+    final public function delete($key)
+    {
+        $result = $this->getMapData($key)->delete($key);
+        $this->size -= $result ? 1 : 0;
+
+        return $result;
+    }
+
+    private function isKey($key)
+    {
+        return \is_scalar($key);
+    }
+
+    private function getMapData($key): CacheInterface
+    {
+        if ($this->isKey($key)) {
+            return $this->__data__[\is_string($key) ? 'string' : 'hash'];
+        }
+
+        return $this->__data__['map'];
+    }
+}
diff --git a/src/Math/add.php b/src/Math/add.php
new file mode 100644
index 0000000..5d53cb4
--- /dev/null
+++ b/src/Math/add.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+use function _\internal\createMathOperation;
+
+/**
+ * Adds two numbers.
+ *
+ * @category Math
+ *
+ * @param int|float|string $augend The first number in an addition.
+ * @param int|float|string $addend The second number in an addition.
+ *
+ * @return int|float Returns the total.
+ *
+ * @example
+ * <code>
+ * add(6, 4);
+ * // => 10
+ * </code>
+ */
+function add($augend, $addend)
+{
+    return createMathOperation(function ($augend, $addend) {
+        return $augend + $addend;
+    }, 0)($augend, $addend);
+}
diff --git a/src/Math/max.php b/src/Math/max.php
new file mode 100644
index 0000000..bc61451
--- /dev/null
+++ b/src/Math/max.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+/**
+ * Computes the maximum value of `array`. If `array` is empty or falsey, null is returned.
+ *
+ * @category Math
+ *
+ * @param array|null $array The array to iterate over.
+ *
+ * @return int|null Returns the maximum value.
+ * @example
+ * <code>
+ * max([4, 2, 8, 6]);
+ * // => 8
+ *
+ * max([]);
+ * // => null
+ * </code>
+ */
+function max(?array $array): ?int
+{
+    return $array ? \max($array) : null;
+}
diff --git a/src/Math/maxBy.php b/src/Math/maxBy.php
new file mode 100644
index 0000000..3127605
--- /dev/null
+++ b/src/Math/maxBy.php
@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+use function _\internal\baseIteratee;
+
+/**
+ * This method is like `max` except that it accepts `iteratee` which is
+ * invoked for each element in `array` to generate the criterion by which
+ * the value is ranked. The iteratee is invoked with one argument: (value).
+ *
+ * @category Math
+ *
+ * @param array           $array    The array to iterate over.
+ * @param callable|string $iteratee The iteratee invoked per element.
+ *
+ * @return mixed Returns the maximum value.
+ * @example
+ * <code>
+ * $objects = [['n' => 1], ['n' => 2]];
+ *
+ * maxBy($objects, function($o) { return $o['n']; });
+ * // => ['n' => 2]
+ *
+ * // The `property` iteratee shorthand.
+ * maxBy($objects, 'n');
+ * // => ['n' => 2]
+ * </code>
+ */
+function maxBy(?array $array, $iteratee)
+{
+    $iteratee = baseIteratee($iteratee);
+    $result = null;
+    $computed = null;
+
+    foreach ($array as $key => $value) {
+        $current = $iteratee($value);
+
+        if (null !== $current && (null === $computed ? ($current === $current) : $current > $computed)) {
+            $computed = $current;
+            $result = $value;
+        }
+    }
+
+    return $result;
+}
diff --git a/src/Number/clamp.php b/src/Number/clamp.php
index 7ef9017..2ab5ddc 100644
--- a/src/Number/clamp.php
+++ b/src/Number/clamp.php
@@ -16,9 +16,9 @@
  *
  * @category Number
  *
- * @param    int number The number to clamp.
- * @param    int lower The lower bound.
- * @param    int upper The upper bound.
+ * @param int $number The number to clamp.
+ * @param int $lower  The lower bound.
+ * @param int $upper  The upper bound.
  *
  * @return int Returns the clamped number.
  *
@@ -37,4 +37,4 @@ function clamp(int $number, int $lower, int $upper): int
     $number = $number >= $lower ? $number : $lower;
 
     return $number;
-}
\ No newline at end of file
+}
diff --git a/src/Number/inRange.php b/src/Number/inRange.php
index 8f78f26..f1408ae 100644
--- a/src/Number/inRange.php
+++ b/src/Number/inRange.php
@@ -19,11 +19,12 @@
  *
  * @category Number
  *
- * @param float number The number to check.
- * @param float $start The start of the range.
- * @param float $end   The end of the range.
+ * @param float $number The number to check.
+ * @param float $start  The start of the range.
+ * @param float $end    The end of the range.
  *
  * @return boolean Returns `true` if `number` is in the range, else `false`.
+ *
  * @example
  * <code>
  * inRange(3, 2, 4)
@@ -50,10 +51,10 @@
  */
 function inRange(float $number, float $start = 0, float $end = 0): bool
 {
-    if (0 === $end || 0.0 === $end) {
+    if (0.0 === $end) {
         $end = $start;
         $start = 0;
     }
 
     return $number >= \min($start, $end) && $number < \max($start, $end);
-}
\ No newline at end of file
+}
diff --git a/src/Number/random.php b/src/Number/random.php
index bdc158e..8d322af 100644
--- a/src/Number/random.php
+++ b/src/Number/random.php
@@ -19,14 +19,14 @@
  *
  * @category Number
  *
- * @param    int|float $lower    The lower bound.
- * @param    int|float $upper    The upper bound.
- * @param    bool      $floating Specify returning a floating-point number.
+ * @param int|float|bool $lower    The lower bound.
+ * @param int|float|bool $upper    The upper bound.
+ * @param bool|null      $floating Specify returning a floating-point number.
  *
  * @return int|float Returns the random number.
  *
  * @example
- *
+ * <code>
  * random(0, 5)
  * // => an integer between 0 and 5
  *
@@ -38,6 +38,7 @@
  *
  * random(1.2, 5.2)
  * // => a floating-point number between 1.2 and 5.2
+ * </code>
  */
 function random($lower = null, $upper = null, $floating = null)
 {
@@ -45,7 +46,7 @@ function random($lower = null, $upper = null, $floating = null)
         if (\is_bool($upper)) {
             $floating = $upper;
             $upper = null;
-        } else if (\is_bool($lower)) {
+        } elseif (\is_bool($lower)) {
             $floating = $lower;
             $lower = null;
         }
@@ -54,7 +55,7 @@ function random($lower = null, $upper = null, $floating = null)
     if (null === $lower && null === $upper) {
         $lower = 0;
         $upper = 1;
-    } else if (null === $upper) {
+    } elseif (null === $upper) {
         $upper = $lower;
         $lower = 0;
     }
@@ -73,5 +74,5 @@ function random($lower = null, $upper = null, $floating = null)
         return $lower + \abs($upper - $lower) * \mt_rand(0, $randMax) / $randMax;
     }
 
-    return \rand((int) $lower, (int) $upper);
+    return \random_int((int) $lower, (int) $upper);
 }
diff --git a/src/Object/get.php b/src/Object/get.php
new file mode 100644
index 0000000..3a0c66d
--- /dev/null
+++ b/src/Object/get.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2019
+ */
+
+namespace _;
+
+use function _\internal\baseGet;
+
+/**
+ * Gets the value at path of object. If the resolved value is null the defaultValue is returned in its place.
+ *
+ * @category Object
+ *
+ * @param mixed $object The associative array or object to fetch value from
+ * @param array|string $path Dot separated or array of string
+ * @param mixed $defaultValue (optional)The value returned for unresolved or null values.
+ *
+ * @return mixed Returns the resolved value.
+ *
+ * @author punit-kulal
+ *
+ * @example
+ * <code>
+ * $sampleArray = ["key1" => ["key2" => ["key3" => "val1", "key4" => ""]]];
+ * get($sampleArray, 'key1.key2.key3');
+ * // => "val1"
+ *
+ * get($sampleArray, 'key1.key2.key5', "default");
+ * // => "default"
+ *
+ * get($sampleArray, 'key1.key2.key4', "default");
+ * // => ""
+ * </code>
+ */
+function get($object, $path, $defaultValue = null)
+{
+    return ($object !== null ? baseGet($object, $path) : null) ?? $defaultValue;
+}
diff --git a/src/Object/pick.php b/src/Object/pick.php
new file mode 100644
index 0000000..9813514
--- /dev/null
+++ b/src/Object/pick.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _;
+
+use function _\internal\basePick;
+use function _\internal\flatRest;
+
+/**
+ * Creates an object composed of the picked `object` properties.
+ *
+ * @category Object
+ *
+ * @param object          $object The source object.
+ * @param string|string[] $paths  The property paths to pick.
+ *
+ * @return \stdClass Returns the new object.
+ * @example
+ * <code>
+ * $object = (object) ['a' => 1, 'b' => '2', 'c' => 3];
+ *
+ * pick($object, ['a', 'c']);
+ * // => (object) ['a' => 1, 'c' => 3]
+ * </code>
+ */
+function pick($object, $paths): \stdClass
+{
+    return flatRest(function ($object, $paths) {
+        return basePick($object, $paths);
+    })($object, $paths);
+}
diff --git a/src/Object/pickBy.php b/src/Object/pickBy.php
new file mode 100644
index 0000000..7d85cc0
--- /dev/null
+++ b/src/Object/pickBy.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+use function _\internal\arrayMap;
+use function _\internal\baseIteratee;
+use function _\internal\basePickBy;
+
+/**
+ * Creates an object composed of the `object` properties `predicate` returns
+ * truthy for. The predicate is invoked with two arguments: (value, key).
+ *
+ * @category Object
+ *
+ * @param object|null $object    The source object.
+ * @param callable    $predicate The function invoked per property.
+ *
+ * @return \stdClass Returns the new object.
+ * @example
+ * <code>
+ * $object = (object) ['a' => 1, 'b' => 'abc', 'c' => 3];
+ *
+ * pickBy(object, 'is_numeric');
+ * // => (object) ['a' => 1, 'c' => 3]
+ * </code>
+ */
+function pickBy($object, callable $predicate): \stdClass
+{
+    if (null === $object) {
+        return new \stdClass;
+    }
+
+    $props = arrayMap(\array_keys(\get_object_vars($object)), function ($prop) {
+        return [$prop];
+    });
+    $predicate = baseIteratee($predicate);
+
+    return basePickBy($object, $props, function ($value, $path) use ($predicate) {
+        return $predicate($value, $path[0]);
+    });
+}
diff --git a/src/Seq/chain.php b/src/Seq/chain.php
new file mode 100644
index 0000000..63e3149
--- /dev/null
+++ b/src/Seq/chain.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a `lodash` wrapper instance that wraps `value` with explicit method
+ * chain sequences enabled. The result of such sequences must be unwrapped
+ * with `->value()`.
+ *
+ * @category Seq
+ *
+ * @param mixed $value The value to wrap.
+ *
+ * @return \_ Returns the new `lodash` wrapper instance.
+ * @example
+ * <code>
+ * $users = [
+ *   ['user' => 'barney',  'age' => 36],
+ *   ['user' => 'fred',    'age' => 40],
+ *   ['user' => 'pebbles', 'age' => 1 ],
+ * ];
+ *
+ * $youngest = chain($users)
+ *   ->sortBy('age')
+ *   ->map(function($o) {
+ *     return $o['user'] . ' is ' . $o['age'];
+ *   })
+ *   ->head()
+ *   ->value();
+ * // => 'pebbles is 1'
+ * </code>
+ */
+function chain($value): \_
+{
+    /** @var \_ $result */
+    $result = __($value);
+    $result->__chain__ = true;
+
+    return $result;
+}
diff --git a/src/String/camelCase.php b/src/String/camelCase.php
index 1886062..e669e5a 100644
--- a/src/String/camelCase.php
+++ b/src/String/camelCase.php
@@ -37,4 +37,4 @@ function camelCase(string $string): string
     return \lcfirst(\array_reduce(words(\preg_replace("/['\\x{2019}]/u", '', $string)), function ($result, $word) {
         return $result.capitalize(\strtolower($word));
     }, ''));
-}
\ No newline at end of file
+}
diff --git a/src/String/capitalize.php b/src/String/capitalize.php
index 54df344..c6403f2 100644
--- a/src/String/capitalize.php
+++ b/src/String/capitalize.php
@@ -30,4 +30,4 @@
 function capitalize(string $string): string
 {
     return \ucfirst(\mb_strtolower($string));
-}
\ No newline at end of file
+}
diff --git a/src/String/deburr.php b/src/String/deburr.php
index 10ca5a7..a850d78 100644
--- a/src/String/deburr.php
+++ b/src/String/deburr.php
@@ -96,9 +96,10 @@
  * @return string Returns the deburred string.
  *
  * @example
- *
+ * <code>
  * deburr('déjà vu')
  * // => 'deja vu'
+ * </code>
  */
 function deburr(string $string): string
 {
@@ -110,4 +111,4 @@ function ($pattern) {
     );
 
     return \preg_replace(rsCombo, '', \preg_replace($patterns, \array_values(deburredLetters), $string));
-}
\ No newline at end of file
+}
diff --git a/src/String/endsWith.php b/src/String/endsWith.php
index 1b84f65..677effb 100644
--- a/src/String/endsWith.php
+++ b/src/String/endsWith.php
@@ -40,11 +40,11 @@ function endsWith(string $string, string $target, int $position = null): bool
 
     if ($position < 0) {
         $position = 0;
-    } else if ($position > $length) {
+    } elseif ($position > $length) {
         $position = $length;
     }
 
     $position -= \strlen($target);
 
     return $position >= 0 && \substr($string, $position, \strlen($target)) === $target;
-}
\ No newline at end of file
+}
diff --git a/src/String/escape.php b/src/String/escape.php
index 416a956..680ca98 100644
--- a/src/String/escape.php
+++ b/src/String/escape.php
@@ -40,4 +40,4 @@
 function escape(string $string)
 {
     return \htmlentities($string);
-}
\ No newline at end of file
+}
diff --git a/src/String/kebabCase.php b/src/String/kebabCase.php
index 0839402..bccbc43 100644
--- a/src/String/kebabCase.php
+++ b/src/String/kebabCase.php
@@ -35,4 +35,4 @@
 function kebabCase(string $string)
 {
     return \implode('-', \array_map('\strtolower', words(\preg_replace("/['\x{2019}]/u", '', $string))));
-}
\ No newline at end of file
+}
diff --git a/src/String/lowerCase.php b/src/String/lowerCase.php
index c1aeba9..0266600 100644
--- a/src/String/lowerCase.php
+++ b/src/String/lowerCase.php
@@ -36,4 +36,4 @@
 function lowerCase(string $string)
 {
     return \implode(' ', \array_map('\strtolower', words(\preg_replace(reQuotes, '', $string))));
-}
\ No newline at end of file
+}
diff --git a/src/String/lowerFirst.php b/src/String/lowerFirst.php
index cfe8597..51d4f96 100644
--- a/src/String/lowerFirst.php
+++ b/src/String/lowerFirst.php
@@ -32,4 +32,4 @@
 function lowerFirst(string $string): string
 {
     return \lcfirst($string);
-}
\ No newline at end of file
+}
diff --git a/src/String/pad.php b/src/String/pad.php
index 7bb8cde..efb76bf 100644
--- a/src/String/pad.php
+++ b/src/String/pad.php
@@ -38,4 +38,4 @@
 function pad(string $string, int $length, string $chars = ' '): string
 {
     return \str_pad($string, $length, $chars, \STR_PAD_BOTH);
-}
\ No newline at end of file
+}
diff --git a/src/String/padStart.php b/src/String/padStart.php
index c3ffb19..e7c6443 100644
--- a/src/String/padStart.php
+++ b/src/String/padStart.php
@@ -37,4 +37,4 @@
 function padStart(string $string, int $length, string $chars = ' '): string
 {
     return \str_pad($string, $length, $chars, \STR_PAD_LEFT);
-}
\ No newline at end of file
+}
diff --git a/src/String/parseInt.php b/src/String/parseInt.php
index d3ea8cb..9fbe799 100644
--- a/src/String/parseInt.php
+++ b/src/String/parseInt.php
@@ -36,9 +36,9 @@ function parseInt($string, int $radix = null): int
 {
     if (null === $radix) {
         $radix = 10;
-    } else if ($radix) {
+    } elseif ($radix) {
         $radix = +$radix;
     }
 
     return \intval($string, $radix);
-}
\ No newline at end of file
+}
diff --git a/src/String/repeat.php b/src/String/repeat.php
index 58ffa51..c650fd4 100644
--- a/src/String/repeat.php
+++ b/src/String/repeat.php
@@ -36,4 +36,4 @@
 function repeat(string $string, int $n = 1): string
 {
     return \str_repeat($string, $n);
-}
\ No newline at end of file
+}
diff --git a/src/String/replace.php b/src/String/replace.php
index 60e7546..9e308f6 100644
--- a/src/String/replace.php
+++ b/src/String/replace.php
@@ -19,9 +19,9 @@
  *
  * @category String
  *
- * @param string $string  The string to modify.
- * @param string $pattern The pattern to replace.
- * @param    callable|string replacement The match replacement.
+ * @param string          $string      The string to modify.
+ * @param string          $pattern     The pattern to replace.
+ * @param callable|string $replacement The match replacement.
  *
  * @return string Returns the modified string.
  *
@@ -31,23 +31,23 @@
  * // => 'Hi Barney'
  * </code>
  */
-function replace(string $string, string $pattern, $replacement = ''): string
+function replace(string $string, string $pattern, $replacement = null): string
 {
     $callback = function (array $matches) use ($replacement): ?string {
         if (!\array_filter($matches)) {
             return null;
         }
 
-        return $replacement(...$matches);
+        return \is_callable($replacement) ? $replacement(...$matches) : null;
     };
 
     if (\preg_match(reRegExpChar, $pattern)) {
-        if (!is_callable($replacement)) {
-            return \preg_replace($pattern, $replacement, $string);
+        if (!\is_callable($replacement)) {
+            return \preg_replace($pattern, \is_string($replacement) || \is_array($replacement) ? $replacement : '', $string);
         }
 
         return \preg_replace_callback($pattern, $callback, $string);
     }
 
-    return \str_replace($pattern, $replacement, $string);
-}
\ No newline at end of file
+    return \str_replace($pattern, \is_string($replacement) || \is_array($replacement) ? $replacement : '', $string);
+}
diff --git a/src/String/snakeCase.php b/src/String/snakeCase.php
index 3369166..07c3d0f 100644
--- a/src/String/snakeCase.php
+++ b/src/String/snakeCase.php
@@ -19,7 +19,7 @@
  * @param string $string The string to convert.
  * @return string Returns the snake cased string.
  * @example
- *
+ * <code>
  * snakeCase('Foo Bar')
  * // => 'foo_bar'
  *
@@ -28,8 +28,9 @@
  *
  * snakeCase('--FOO-BAR--')
  * // => 'foo_bar'
+ * </code>
  */
 function snakeCase(string $string): string
 {
     return \implode('_', \array_map('\strtolower', words(\preg_replace("/['\x{2019}]/u", '', $string))));
-}
\ No newline at end of file
+}
diff --git a/src/String/split.php b/src/String/split.php
index f001b0b..73916c3 100644
--- a/src/String/split.php
+++ b/src/String/split.php
@@ -19,7 +19,7 @@
  *
  * @category String
  *
- * @param string string The string to split.
+ * @param string $string The string to split.
  * @param string $separator The separator pattern to split by.
  * @param int    $limit     The length to truncate results to.
  *
@@ -30,12 +30,13 @@
  * // => ['a', 'b']
  * </code>
  */
-function split(string $string, string $separator, int $limit = null): array
+function split(string $string, string $separator, int $limit = 0): array
 {
     if (\preg_match(reRegExpChar, $separator)) {
-        return \preg_split($separator, $string, $limit ?? -1, PREG_SPLIT_DELIM_CAPTURE);
+        return \preg_split($separator, $string, $limit ?: -1, PREG_SPLIT_DELIM_CAPTURE) ?: [];
     }
 
+    /** @var array $result */
     $result = \explode($separator, $string);
 
     if ($limit > 0) {
@@ -43,4 +44,4 @@ function split(string $string, string $separator, int $limit = null): array
     }
 
     return $result;
-}
\ No newline at end of file
+}
diff --git a/src/String/startCase.php b/src/String/startCase.php
index a1f5f66..7ffb8cb 100644
--- a/src/String/startCase.php
+++ b/src/String/startCase.php
@@ -35,4 +35,4 @@
 function startCase(string $string)
 {
     return \implode(' ', \array_map('\ucfirst', words(\preg_replace("/['\x{2019}]/u", '', $string))));
-}
\ No newline at end of file
+}
diff --git a/src/String/startsWith.php b/src/String/startsWith.php
index 4860ec8..af01975 100644
--- a/src/String/startsWith.php
+++ b/src/String/startsWith.php
@@ -40,9 +40,9 @@ function startsWith(string $string, string $target, int $position = null): bool
 
     if ($position < 0) {
         $position = 0;
-    } else if ($position > $length) {
+    } elseif ($position > $length) {
         $position = $length;
     }
 
     return $position >= 0 && \substr($string, $position, \strlen($target)) === $target;
-}
\ No newline at end of file
+}
diff --git a/src/String/template.php b/src/String/template.php
index 0063bd8..8b76ef0 100644
--- a/src/String/template.php
+++ b/src/String/template.php
@@ -106,14 +106,13 @@ function template(string $string, array $options = []): callable
         ($options['evaluate'] ?? reNoMatch),
     ]);
 
-    $string = \preg_replace_callback('#'.$reDelimiters.'#u', function ($matches) use (&$options) {
-        list(
-            ,
+    $string = \preg_replace_callback('#'.$reDelimiters.'#u', function ($matches) {
+        [,
             $escapeValue,
             $interpolateValue,
             $esTemplateValue,
             $evaluateValue,
-            ) = \array_merge($matches, \array_fill(\count($matches), 5 - \count($matches), null));
+            ] = \array_merge($matches, \array_fill(\count($matches), 5 - \count($matches), null));
 
         $interpolateValue = $interpolateValue ?: $esTemplateValue;
 
@@ -121,17 +120,17 @@ function template(string $string, array $options = []): callable
 
         if ($escapeValue) {
             $escapeValue = \trim($escapeValue);
-            $source .= "<?=__e(\$${escapeValue});?>";
+            $source .= "<?=__e(\${$escapeValue});?>";
         }
 
         if ($evaluateValue) {
-            $source .= "<?php \n${evaluateValue} ?>";
+            $source .= "<?php \n{$evaluateValue} ?>";
         }
 
         if ($interpolateValue) {
-            $interpolateValue = \trim($interpolateValue ?? $esTemplateValue);
+            $interpolateValue = \trim($interpolateValue);
             $interpolateValue = \preg_replace('#^([\p{L}\p{N}_]+)$#u', '$$1', $interpolateValue);
-            $source .= "<?=${interpolateValue};?>";
+            $source .= "<?={$interpolateValue};?>";
         }
 
         return $source;
@@ -143,12 +142,17 @@ function template(string $string, array $options = []): callable
 
     $imports = $options['imports'] ?? [];
 
-    return new class($string, $imports)
-    {
+    return new class($string, $imports) {
         public $source;
 
+        /**
+         * @var array<string, string>
+         */
         private $imports;
 
+        /**
+         * @param array<string, string> $imports
+         */
         public function __construct(string $source, array $imports)
         {
             $this->source = $source;
@@ -162,13 +166,18 @@ public function __invoke(array $arguments = [])
             foreach ($this->imports as $import => $alias) {
                 if (\class_exists($import)) {
                     $imports .= "use $import as $alias;";
-                } else if (\function_exists($import)) {
+                } elseif (\function_exists($import)) {
                     $imports .= "use function $import as $alias;";
                 }
             }
 
+            /** @var string $file */
             $file = \tempnam(\sys_get_temp_dir(), 'lodashphp');
 
+            if (!$file) {
+                throw new \RuntimeException('Unable to create temporary file for template');
+            }
+
             \file_put_contents($file, "<?php namespace __template; $imports (function() { extract(".\var_export($arguments, true).'); ?>'.$this->source.'<?php })()?>');
 
             $content = attempt(function () use ($file) {
@@ -183,4 +192,4 @@ public function __invoke(array $arguments = [])
             return $content;
         }
     };
-}
\ No newline at end of file
+}
diff --git a/src/String/toLower.php b/src/String/toLower.php
index 8144d68..bab4c7a 100644
--- a/src/String/toLower.php
+++ b/src/String/toLower.php
@@ -34,4 +34,4 @@
 function toLower(string $string): string
 {
     return \strtolower($string);
-}
\ No newline at end of file
+}
diff --git a/src/String/toUpper.php b/src/String/toUpper.php
index 3a0779a..af61dcf 100644
--- a/src/String/toUpper.php
+++ b/src/String/toUpper.php
@@ -29,6 +29,7 @@
  *
  * toUpper('__foo_bar__')
  * // => '__FOO_BAR__'
+ * </code>
  */
 function toUpper(string $string): string
 {
diff --git a/src/String/trim.php b/src/String/trim.php
index 8967999..7bef528 100644
--- a/src/String/trim.php
+++ b/src/String/trim.php
@@ -32,4 +32,4 @@
 function trim(string $string, string $chars = ' '): string
 {
     return \trim($string, $chars);
-}
\ No newline at end of file
+}
diff --git a/src/String/trimEnd.php b/src/String/trimEnd.php
index 4fc55e7..a90e9da 100644
--- a/src/String/trimEnd.php
+++ b/src/String/trimEnd.php
@@ -21,14 +21,15 @@
  *
  * @return string Returns the trimmed string.
  * @example
- *
+ * <code>
  * trimEnd('  abc  ')
  * // => '  abc'
  *
  * trimEnd('-_-abc-_-', '_-')
  * // => '-_-abc'
+ * </code>
  */
 function trimEnd(string $string, string $chars = ' '): string
 {
     return \rtrim($string, $chars);
-}
\ No newline at end of file
+}
diff --git a/src/String/trimStart.php b/src/String/trimStart.php
index fcdbd66..b2351c6 100644
--- a/src/String/trimStart.php
+++ b/src/String/trimStart.php
@@ -32,4 +32,4 @@
 function trimStart(string $string, string $chars = ' '): string
 {
     return \ltrim($string, $chars);
-}
\ No newline at end of file
+}
diff --git a/src/String/truncate.php b/src/String/truncate.php
index d03ae7c..381c0df 100644
--- a/src/String/truncate.php
+++ b/src/String/truncate.php
@@ -101,14 +101,14 @@ function truncate($string, array $options = [])
                 $newEnd = \end($match[0])[1];
             }
 
-            $result = \substr($result, 0, null === $newEnd ? $end : $newEnd);
+            $result = \substr($result, 0, $newEnd ?? $end);
         }
-    } else if (\strpos($string, $separator) !== $end) {
+    } elseif (\strpos($string, $separator) !== $end) {
         $index = \strrpos($result, $separator);
-        if ($index > -1) {
+        if (false !== $index) {
             $result = \substr($result, 0, $index);
         }
     }
 
     return $result.$omission;
-}
\ No newline at end of file
+}
diff --git a/src/String/unescape.php b/src/String/unescape.php
index 7aeb89d..779cf06 100644
--- a/src/String/unescape.php
+++ b/src/String/unescape.php
@@ -30,4 +30,4 @@
 function unescape(string $string): string
 {
     return \html_entity_decode($string);
-}
\ No newline at end of file
+}
diff --git a/src/String/upperCase.php b/src/String/upperCase.php
index 378f348..149b39d 100644
--- a/src/String/upperCase.php
+++ b/src/String/upperCase.php
@@ -32,4 +32,4 @@
 function upperCase(string $string)
 {
     return \implode(' ', \array_map('\strtoupper', words(\preg_replace(reQuotes, '', $string))));
-}
\ No newline at end of file
+}
diff --git a/src/String/upperFirst.php b/src/String/upperFirst.php
index ef27478..7343905 100644
--- a/src/String/upperFirst.php
+++ b/src/String/upperFirst.php
@@ -31,4 +31,4 @@
 function upperFirst(string $string): string
 {
     return \ucfirst($string);
-}
\ No newline at end of file
+}
diff --git a/src/String/words.php b/src/String/words.php
index 1cd00c8..1bd86c7 100644
--- a/src/String/words.php
+++ b/src/String/words.php
@@ -53,4 +53,4 @@ function words(string $string, string $pattern = null): array
     }
 
     return [];
-}
\ No newline at end of file
+}
diff --git a/src/Util/attempt.php b/src/Util/attempt.php
index bc6211a..2b1895b 100644
--- a/src/Util/attempt.php
+++ b/src/Util/attempt.php
@@ -18,7 +18,7 @@
  * @category Util
  *
  * @param callable $func The function to attempt.
- * @param mixed[]  $args The arguments to invoke `func` with.
+ * @param array<int, mixed>  $args The arguments to invoke `func` with.
  *
  * @return mixed|\Throwable Returns the `func` result or error object.
  *
@@ -41,4 +41,4 @@ function attempt(callable $func, ...$args)
     } catch (\ParseError | \Error | \Throwable | \SoapFault | \DOMException | \PDOException $e) {
         return $e;
     }
-}
\ No newline at end of file
+}
diff --git a/src/Util/defaultTo.php b/src/Util/defaultTo.php
new file mode 100644
index 0000000..79b8baf
--- /dev/null
+++ b/src/Util/defaultTo.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2019
+ */
+
+namespace _;
+
+/**
+ * Checks value to determine whether a default value should be returned in its place.
+ * The defaultValue is returned if value is NaN or null.
+ *
+ * @category Util
+ *
+ * @param mixed $value Any value.
+ * @param mixed $defaultValue Value to return when $value is null or NAN
+ *
+ * @return mixed Returns `value`.
+ *
+ * @author punit-kulal
+ *
+ * @example
+ * <code>
+ * $a = null;
+ *
+ * defaultTo($a, "default");
+ * // => "default"
+ *
+ * $a = "x";
+ *
+ * defaultTo($a, "default");
+ * // => "x"
+ * </code>
+ */
+function defaultTo($value, $defaultValue)
+{
+    return (null !== $value && (is_object($value) || !\is_nan(\floatval($value)))) ? $value : $defaultValue;
+}
diff --git a/src/Util/identity.php b/src/Util/identity.php
index 86c11b6..9b0ef5f 100644
--- a/src/Util/identity.php
+++ b/src/Util/identity.php
@@ -30,4 +30,4 @@
 function identity($value = null)
 {
     return $value;
-}
\ No newline at end of file
+}
diff --git a/src/Util/property.php b/src/Util/property.php
index 233e850..17f75f0 100644
--- a/src/Util/property.php
+++ b/src/Util/property.php
@@ -11,6 +11,8 @@
 
 namespace _;
 
+use Symfony\Component\PropertyAccess\Exception\NoSuchIndexException;
+use Symfony\Component\PropertyAccess\Exception\NoSuchPropertyException;
 use Symfony\Component\PropertyAccess\PropertyAccess;
 
 /**
@@ -18,7 +20,7 @@
  *
  * @category Util
  *
- * @param array|string path The path of the property to get.
+ * @param array|string $path The path of the property to get.
  *
  * @return callable Returns the new accessor function.
  * @example
@@ -42,7 +44,6 @@ function property($path): callable
         ->getPropertyAccessor();
 
     return function ($value, $index = 0, $collection = []) use ($path, $propertyAccess) {
-
         $path = \implode('.', (array) $path);
 
         if (\is_array($value)) {
@@ -61,6 +62,10 @@ function property($path): callable
             }
         }
 
-        return $propertyAccess->getValue($value, $path);
+        try {
+            return $propertyAccess->getValue($value, $path);
+        } catch (NoSuchPropertyException | NoSuchIndexException $e) {
+            return null;
+        }
     };
-}
\ No newline at end of file
+}
diff --git a/src/bootstrap.php b/src/bootstrap.php
index 745a01a..8bc7456 100644
--- a/src/bootstrap.php
+++ b/src/bootstrap.php
@@ -9,6 +9,14 @@
  * @copyright  Copyright (c) 2017
  */
 
-foreach (new RecursiveIteratorIterator(new RecursiveDirectoryIterator(__DIR__, RecursiveDirectoryIterator::SKIP_DOTS)) as $file) {
-    require_once $file->getRealPath();
+if (file_exists($file = __DIR__.'/compiled.php')) {
+    require_once $file;
+} else {
+    require_once __DIR__.'/internal/Traits/CacheDataTrait.php';
+    require_once __DIR__.'/internal/unicode.php';
+    require_once __DIR__.'/CacheInterface.php';
+
+    foreach (new RecursiveIteratorIterator(new RecursiveDirectoryIterator(__DIR__, RecursiveDirectoryIterator::SKIP_DOTS)) as $file) {
+        require_once $file->getRealPath();
+    }
 }
diff --git a/src/internal/Traits/CacheDataTrait.php b/src/internal/Traits/CacheDataTrait.php
new file mode 100644
index 0000000..4700cce
--- /dev/null
+++ b/src/internal/Traits/CacheDataTrait.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal\Traits;
+
+trait CacheDataTrait
+{
+    private $__data__ = [];
+
+    private $size;
+
+    public function getSize(): int
+    {
+        return $this->size;
+    }
+}
diff --git a/src/internal/arrayIncludes.php b/src/internal/arrayIncludes.php
index 5d56cbd..3c95463 100644
--- a/src/internal/arrayIncludes.php
+++ b/src/internal/arrayIncludes.php
@@ -16,4 +16,4 @@
 function arrayIncludes(?array $array, $value)
 {
     return null !== $array && indexOf($array, $value, 0) > -1;
-}
\ No newline at end of file
+}
diff --git a/src/internal/arrayIncludesWith.php b/src/internal/arrayIncludesWith.php
index 4cedfba..6b218d1 100644
--- a/src/internal/arrayIncludesWith.php
+++ b/src/internal/arrayIncludesWith.php
@@ -22,4 +22,4 @@ function arrayIncludesWith(?array $array, $value, callable $comparator)
     }
 
     return false;
-}
\ No newline at end of file
+}
diff --git a/src/internal/arrayMap.php b/src/internal/arrayMap.php
new file mode 100644
index 0000000..2a56b5d
--- /dev/null
+++ b/src/internal/arrayMap.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function arrayMap(?array $array, callable $iteratee)
+{
+    $index = -1;
+    $length = null === $array ? 0 : \count($array);
+    $result = [];
+
+    while (++$index < $length) {
+        $result[$index] = $iteratee($array[$index], $index, $array);
+    }
+
+    return $result;
+}
diff --git a/src/internal/arrayPush.php b/src/internal/arrayPush.php
new file mode 100644
index 0000000..a0af2b3
--- /dev/null
+++ b/src/internal/arrayPush.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function arrayPush(&$array, $values)
+{
+    $index = -1;
+    $length = \is_array($values) ? \count($values) : \strlen($values);
+    $offset = \count($array);
+
+    while (++$index < $length) {
+        $array[$offset + $index] = $values[$index];
+    }
+
+    return $array;
+}
diff --git a/src/internal/assocIndexOf.php b/src/internal/assocIndexOf.php
new file mode 100644
index 0000000..b8cb19a
--- /dev/null
+++ b/src/internal/assocIndexOf.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+use function _\eq;
+
+function assocIndexOf(array $array, $key): int
+{
+    $length = \count($array);
+    while ($length--) {
+        if (eq($array[$length][0], $key)) {
+            return $length;
+        }
+    }
+
+    return -1;
+}
diff --git a/src/internal/baseFlatten.php b/src/internal/baseFlatten.php
index 9072d37..61a7a03 100644
--- a/src/internal/baseFlatten.php
+++ b/src/internal/baseFlatten.php
@@ -16,15 +16,15 @@
  *
  * @private
  *
- * @param array    $array     The array to flatten.
- * @param int      $depth     The maximum recursion depth.
- * @param callable $predicate The function invoked per iteration [isFlattenable].
- * @param bool     $isStrict  Restrict to values that pass `predicate` checks.
- * @param array    $result    The initial result value.
+ * @param array|null    $array     The array to flatten.
+ * @param int           $depth     The maximum recursion depth.
+ * @param callable|null $predicate The function invoked per iteration [isFlattenable].
+ * @param bool|null     $isStrict  Restrict to values that pass `predicate` checks.
+ * @param array|null    $result    The initial result value.
  *
  * @return array Returns the new flattened array.
  */
-function baseFlatten(?array $array, float $depth, callable $predicate = null, bool $isStrict = null, array $result = null): array
+function baseFlatten(?array $array, int $depth, callable $predicate = null, bool $isStrict = null, array $result = null): array
 {
     $result = $result ?? [];
 
@@ -40,12 +40,12 @@ function baseFlatten(?array $array, float $depth, callable $predicate = null, bo
                 // Recursively flatten arrays (susceptible to call stack limits).
                 $result = baseFlatten($value, $depth - 1, $predicate, $isStrict, $result);
             } else {
-                $result = \array_merge($result, $value);
+                arrayPush($result, $value);
             }
-        } else if (!$isStrict) {
-            $result[count($result)] = $value;
+        } elseif (!$isStrict) {
+            $result[\count($result)] = $value;
         }
     }
 
     return $result;
-}
\ No newline at end of file
+}
diff --git a/src/internal/baseGet.php b/src/internal/baseGet.php
new file mode 100644
index 0000000..a9ff96a
--- /dev/null
+++ b/src/internal/baseGet.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+use function _\property;
+
+function baseGet($object, $path)
+{
+    $path = castPath($path, $object);
+
+    $index = 0;
+    $length = \count($path);
+
+    while ($object !== null && !is_scalar($object) && $index < $length) {
+        $object = property(toKey($path[$index++]))($object);
+    }
+
+    return ($index > 0  && $index === $length) ? $object : null;
+}
diff --git a/src/internal/baseIndexOfWith.php b/src/internal/baseIndexOfWith.php
index 1eb7f39..5a391c5 100644
--- a/src/internal/baseIndexOfWith.php
+++ b/src/internal/baseIndexOfWith.php
@@ -23,4 +23,4 @@ function baseIndexOfWith(array $array, $value, int $fromIndex, $comparator)
     }
 
     return -1;
-}
\ No newline at end of file
+}
diff --git a/src/internal/baseIntersection.php b/src/internal/baseIntersection.php
index 080a6cd..e366d37 100644
--- a/src/internal/baseIntersection.php
+++ b/src/internal/baseIntersection.php
@@ -41,15 +41,15 @@ function baseIntersection($arrays, ?callable $iteratee, $comparator = null)
         $computed = $iteratee ? $iteratee($value) : $value;
 
         $value = ($comparator ?: $value !== 0) ? $value : 0;
-        if (!($seen ? isset($seen[$computed]) : $includes($result, $computed, $comparator))) {
+        if (!($seen ? \is_scalar($computed) && isset($seen[$computed]) : $includes($result, $computed, $comparator))) {
             $othIndex = $othLength;
             while (--$othIndex) {
                 $cache = $caches[$othIndex];
-                if (!($cache ? isset($cache[$computed]) : $includes($arrays[$othIndex], $computed, $comparator))) {
+                if (!(!empty($cache) ? isset($cache[$computed]) : $includes($arrays[$othIndex], $computed, $comparator))) {
                     continue 2;
                 }
             }
-            if ($seen) {
+            if (empty($seen)) {
                 $seen[] = $computed;
             }
 
@@ -58,4 +58,4 @@ function baseIntersection($arrays, ?callable $iteratee, $comparator = null)
     }
 
     return $result;
-}
\ No newline at end of file
+}
diff --git a/src/internal/baseInvoke.php b/src/internal/baseInvoke.php
new file mode 100644
index 0000000..1170f84
--- /dev/null
+++ b/src/internal/baseInvoke.php
@@ -0,0 +1,24 @@
+<?php
+
+// No 'declare(strict_types=1)' here as the invoked method needs to use weak-type{
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+use function _\last;
+
+function baseInvoke($object, $path, $args)
+{
+    $path = castPath($path, $object);
+    $object = parent($object, $path);
+    /** @var callable|null $func */
+    $func = null === $object ? $object : [$object, toKey(last($path))];
+
+    return \is_callable($func) ? $func($object, ...$args) : null;
+}
diff --git a/src/internal/baseIteratee.php b/src/internal/baseIteratee.php
index 22efba8..13cc2af 100644
--- a/src/internal/baseIteratee.php
+++ b/src/internal/baseIteratee.php
@@ -30,4 +30,4 @@ function baseIteratee($value): callable
     }
 
     return property($value);
-}
\ No newline at end of file
+}
diff --git a/src/internal/baseMatches.php b/src/internal/baseMatches.php
index 400c027..3f39f4f 100644
--- a/src/internal/baseMatches.php
+++ b/src/internal/baseMatches.php
@@ -21,7 +21,7 @@ function baseMatches($source): callable
             return true;
         }
 
-        if (\is_array($source) || $source instanceof \Traversable) {
+        if (\is_iterable($source)) {
             foreach ($source as $k => $v) {
                 if (!isEqual(property($k)($value, $index, $collection), $v)) {
                     return false;
@@ -33,4 +33,4 @@ function baseMatches($source): callable
 
         return false;
     };
-}
\ No newline at end of file
+}
diff --git a/src/internal/baseMatchesProperty.php b/src/internal/baseMatchesProperty.php
index 2f48dd9..f1d7797 100644
--- a/src/internal/baseMatchesProperty.php
+++ b/src/internal/baseMatchesProperty.php
@@ -19,4 +19,4 @@ function baseMatchesProperty($property, $source): callable
     return function ($value, $index, $collection) use ($property, $source) {
         return isEqual(property($property)($value, $index, $collection), $source);
     };
-}
\ No newline at end of file
+}
diff --git a/src/internal/baseOrderBy.php b/src/internal/baseOrderBy.php
new file mode 100644
index 0000000..d8c2d89
--- /dev/null
+++ b/src/internal/baseOrderBy.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+use function _\map;
+use function _\sortBy;
+
+function baseOrderBy(iterable $collection, array $iteratees, array $orders): array
+{
+    $index = -1;
+    $iteratees = arrayMap($iteratees, baseUnary('\_\internal\baseIteratee'));
+
+    $result = map($collection, function ($value) use ($iteratees, &$index) {
+        $criteria = arrayMap($iteratees, function ($iteratee) use ($value) {
+            return $iteratee($value);
+        });
+
+        return ['criteria' => $criteria, 'index' => ++$index, 'value' => $value];
+    });
+
+    return map(sortBy($result, function ($object, $other) use ($orders) {
+        return compareMultiple($object, $other, $orders);
+    }), 'value');
+}
diff --git a/src/internal/basePick.php b/src/internal/basePick.php
new file mode 100644
index 0000000..477ab46
--- /dev/null
+++ b/src/internal/basePick.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function basePick($object, $paths): \stdClass
+{
+    return basePickBy($object, $paths, function ($value, $path) use ($object) {
+        return property_exists($object, $path) || method_exists($object, 'get'.(ucfirst($path)));
+    });
+}
diff --git a/src/internal/basePickBy.php b/src/internal/basePickBy.php
new file mode 100644
index 0000000..3176a70
--- /dev/null
+++ b/src/internal/basePickBy.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function basePickBy($object, $paths, callable $predicate): \stdClass
+{
+    $index = -1;
+    $length = \is_array($paths) ? \count($paths) : \strlen($paths);
+    $result = new \stdClass();
+
+    while (++$index < $length) {
+        $path = $paths[$index];
+        $value = baseGet($object, $path);
+
+        if ($predicate($value, $path)) {
+            baseSet($result, castPath($path, $object), $value);
+        }
+    }
+
+    return $result;
+}
diff --git a/src/internal/baseProperty.php b/src/internal/baseProperty.php
index cd14aa7..803596e 100644
--- a/src/internal/baseProperty.php
+++ b/src/internal/baseProperty.php
@@ -14,13 +14,13 @@
 /**
  * The base implementation of `_.property` without support for deep paths.
  *
- * @param string $key The key of the property to get.
+ * @param mixed $key The key of the property to get.
  *
  * @return callable Returns the new accessor function.
  */
-function baseProperty(string $key)
+function baseProperty($key)
 {
     return function ($object) use ($key) {
         return null === $object ? null : $object[$key];
     };
-}
\ No newline at end of file
+}
diff --git a/src/internal/basePullAll.php b/src/internal/basePullAll.php
index 788e761..9b69ae3 100644
--- a/src/internal/basePullAll.php
+++ b/src/internal/basePullAll.php
@@ -13,7 +13,7 @@
 
 function basePullAll(&$array, array $values, ?callable $iteratee, callable $comparator = null)
 {
-    $indexOf = $comparator ? '_\internal\baseIndexOfWith' : '_\indexOf';
+    $indexOf = $comparator ? '_\\internal\\baseIndexOfWith' : '_\\indexOf';
 
     $seen = $array;
 
@@ -34,4 +34,4 @@ function basePullAll(&$array, array $values, ?callable $iteratee, callable $comp
     }
 
     return $array;
-}
\ No newline at end of file
+}
diff --git a/src/internal/baseReduce.php b/src/internal/baseReduce.php
new file mode 100644
index 0000000..9d0f360
--- /dev/null
+++ b/src/internal/baseReduce.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function baseReduce(iterable $array, $iteratee, $accumulator, $initAccum = null)
+{
+    $length = \is_array($array) || $array instanceof \Countable ? \count($array) : 0;
+
+    if ($initAccum && $length) {
+        $accumulator = \current($array);
+    }
+
+    foreach ($array as $key => $value) {
+        $accumulator = $iteratee($accumulator, $value, $key, $array);
+    }
+
+    return $accumulator;
+}
diff --git a/src/internal/baseRest.php b/src/internal/baseRest.php
new file mode 100644
index 0000000..95094d0
--- /dev/null
+++ b/src/internal/baseRest.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function baseRest(callable $func, $start = null): callable
+{
+    return overRest($func, $start, '\_\identity');
+}
diff --git a/src/internal/baseSet.php b/src/internal/baseSet.php
new file mode 100644
index 0000000..204a908
--- /dev/null
+++ b/src/internal/baseSet.php
@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function baseSet($object, $path, $value, callable $customizer = null)
+{
+    if (!\is_object($object)) {
+        return $object;
+    }
+
+    $path = castPath($path, $object);
+
+    $index = -1;
+    $length = \count($path);
+    $lastIndex = $length - 1;
+    $nested = $object;
+
+    while ($nested !== null && ++$index < $length) {
+        $key = toKey($path[$index]);
+
+        if ($index !== $lastIndex) {
+            $objValue = \is_array($nested) ? ($nested[$key] ?? null) : ($nested->$key ?? null);
+            $newValue = $customizer ? $customizer($objValue, $key, $nested) : $objValue;
+            if (null === $newValue) {
+                $newValue = \is_object($objValue) ? $objValue : (\is_numeric($path[$index + 1]) ? [] : new \stdClass());
+            }
+
+            if (\is_array($nested)) {
+                $nested[$key] = $newValue;
+            } else {
+                $nested->{$key} = $newValue;
+            }
+
+            if (\is_array($nested)) {
+                $nested = &$nested[$key];
+            } else {
+                $nested = &$nested->$key;
+            }
+
+            continue;
+        }
+
+        $nested->{$key} = $value;
+    }
+
+    return $object;
+}
diff --git a/src/internal/baseTimes.php b/src/internal/baseTimes.php
new file mode 100644
index 0000000..cfc60b6
--- /dev/null
+++ b/src/internal/baseTimes.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function baseTimes(int $n, callable $iteratee)
+{
+    $index = -1;
+    $result = [];
+
+    while (++$index < $n) {
+        $result[$index] = $iteratee($index);
+    }
+
+    return $result;
+}
diff --git a/src/internal/baseUnary.php b/src/internal/baseUnary.php
new file mode 100644
index 0000000..ddfbf80
--- /dev/null
+++ b/src/internal/baseUnary.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function baseUnary($func)
+{
+    return function ($value) use ($func) {
+        return $func($value);
+    };
+}
diff --git a/src/internal/baseUniq.php b/src/internal/baseUniq.php
new file mode 100644
index 0000000..1445b74
--- /dev/null
+++ b/src/internal/baseUniq.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace _\internal;
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+function baseUniq(array $array, callable $iteratee = null, callable $comparator = null)
+{
+    $index = -1;
+    $includes = '\_\internal\arrayIncludes';
+    $length = \count($array);
+    $isCommon = true;
+    $result = [];
+    $seen = $result;
+
+    if ($comparator) {
+        $isCommon = false;
+        $includes = '\_\internal\arrayIncludesWith';
+    } else {
+        $seen = $iteratee ? [] : $result;
+    }
+
+    while (++$index < $length) {
+        $value = $array[$index];
+        $computed = $iteratee ? $iteratee($value) : $value;
+
+        $value = ($comparator || $value !== 0) ? $value : 0;
+
+        if ($isCommon && $computed) {
+            $seenIndex = \count($seen);
+            while ($seenIndex--) {
+                if ($seen[$seenIndex] === $computed) {
+                    continue 2;
+                }
+            }
+            if ($iteratee) {
+                $seen[] = $computed;
+            }
+
+            $result[] = $value;
+        } elseif (!$includes($result, $computed, $comparator)) {
+            if ($seen !== $result) {
+                $seen[] = $computed;
+            }
+            $result[] = $value;
+        }
+    }
+
+    return $result;
+}
diff --git a/src/internal/castPath.php b/src/internal/castPath.php
new file mode 100644
index 0000000..6c2ea8e
--- /dev/null
+++ b/src/internal/castPath.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function castPath($value, $object): array
+{
+    if (\is_array($value)) {
+        return $value;
+    }
+
+    return isKey($value, $object) ? [$value] : stringToPath((string) $value);
+}
diff --git a/src/internal/castSlice.php b/src/internal/castSlice.php
index 4e945b5..6d50495 100644
--- a/src/internal/castSlice.php
+++ b/src/internal/castSlice.php
@@ -25,7 +25,7 @@
 function castSlice(array $array, int $start, ?int $end = null): array
 {
     $length = \count($array);
-    $end = null === $end ? $length : $end;
+    $end = $end ?? $length;
 
     return (!$start && $end >= $length) ? $array : \array_slice($array, $start, $end);
-}
\ No newline at end of file
+}
diff --git a/src/internal/compareMultiple.php b/src/internal/compareMultiple.php
new file mode 100644
index 0000000..ec345de
--- /dev/null
+++ b/src/internal/compareMultiple.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function compareMultiple($object, $other, $orders)
+{
+    $index = -1;
+    $objCriteria = $object['criteria'];
+    $othCriteria = $other['criteria'];
+    $length = \count($objCriteria);
+    $ordersLength = \count($orders);
+
+    while (++$index < $length) {
+        $result = $objCriteria[$index] <=> $othCriteria[$index];
+        if ($result) {
+            if ($index >= $ordersLength) {
+                return $result;
+            }
+            $order = $orders[$index];
+
+            return $result * ('desc' === $order ? -1 : 1);
+        }
+    }
+
+    return $object['index'] - $other['index'];
+}
diff --git a/src/internal/createAggregator.php b/src/internal/createAggregator.php
new file mode 100644
index 0000000..ea63c5a
--- /dev/null
+++ b/src/internal/createAggregator.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+use function _\each;
+
+function createAggregator($setter, $initializer = null)
+{
+    return function ($collection, $iteratee) use ($setter, $initializer) {
+        $accumulator = null !== $initializer ? $initializer() : [];
+
+        $func = function ($collection, $setter, &$accumulator, $iteratee) {
+            each($collection, function ($value, $key, $collection) use ($setter, &$accumulator, $iteratee) {
+                $accumulator = $setter($accumulator, $value, $iteratee($value), $collection);
+            });
+
+            return $accumulator;
+        };
+
+        return $func($collection, $setter, $accumulator, baseIteratee($iteratee));
+    };
+}
diff --git a/src/internal/createMathOperation.php b/src/internal/createMathOperation.php
new file mode 100644
index 0000000..7f4fcf0
--- /dev/null
+++ b/src/internal/createMathOperation.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function createMathOperation(callable $operator, $defaultValue)
+{
+    return function ($value, $other) use ($defaultValue, $operator) {
+        if (null === $value && null === $other) {
+            return $defaultValue;
+        }
+
+        $result = null;
+
+        if (null !== $value) {
+            $result = $value;
+        }
+
+        if (null !== $other) {
+            if (null === $result) {
+                return $other;
+            }
+
+            $result = $operator($value, $other);
+        }
+
+        return $result;
+    };
+}
diff --git a/src/internal/flatRest.php b/src/internal/flatRest.php
new file mode 100644
index 0000000..0cee4a8
--- /dev/null
+++ b/src/internal/flatRest.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function flatRest(callable $func): callable
+{
+    return shortOut(overRest($func, null, '\_\flatten'));
+}
diff --git a/src/internal/hasUnicode.php b/src/internal/hasUnicode.php
index 22c0ceb..117866e 100644
--- a/src/internal/hasUnicode.php
+++ b/src/internal/hasUnicode.php
@@ -26,4 +26,4 @@
 function hasUnicode(string $string): bool
 {
     return \preg_match('#'.reHasUnicode.'#u', $string) > 0;
-}
\ No newline at end of file
+}
diff --git a/src/internal/isFlattenable.php b/src/internal/isFlattenable.php
index fa298e4..f14b5b4 100644
--- a/src/internal/isFlattenable.php
+++ b/src/internal/isFlattenable.php
@@ -22,5 +22,5 @@
  */
 function isFlattenable($value): bool
 {
-    return \is_array($value) && \range(0, \count($value) - 1) === \array_keys($value);
-}
\ No newline at end of file
+    return \is_array($value) && ([] === $value || \range(0, \count($value) - 1) === \array_keys($value));
+}
diff --git a/src/internal/isIterateeCall.php b/src/internal/isIterateeCall.php
index 1b1c792..b9c3169 100644
--- a/src/internal/isIterateeCall.php
+++ b/src/internal/isIterateeCall.php
@@ -24,7 +24,7 @@
  */
 function isIterateeCall($value, $index = null, $object = null)
 {
-    if (!\is_object($object) || !\is_array($object)) {
+    if (!\is_object($object) && !\is_array($object)) {
         return false;
     }
 
@@ -43,4 +43,4 @@ function isIterateeCall($value, $index = null, $object = null)
     }
 
     return false;
-}
\ No newline at end of file
+}
diff --git a/src/internal/isKey.php b/src/internal/isKey.php
index 5d4019a..bb0ce5b 100644
--- a/src/internal/isKey.php
+++ b/src/internal/isKey.php
@@ -12,13 +12,13 @@
 namespace _\internal;
 
 /** Used to match property names within property paths. */
-const reIsDeepProp = '/\.|\[(?:[^[\]]*|(["\'])(?:(?!\1)[^\\]|\\.)*?\1)\]/';
+const reIsDeepProp = '#\.|\[(?:[^[\]]*|(["\'])(?:(?!\1)[^\\\\]|\\.)*?\1)\]#';
 const reIsPlainProp = '/^\w*$/';
 
 /**
  * Checks if `value` is a property name and not a property path.
  *
- * @param mixed value The value to check.
+ * @param mixed        $value  The value to check.
  * @param object|array $object The object to query keys on.
  *
  * @return boolean Returns `true` if `value` is a property name, else `false`.
@@ -29,9 +29,9 @@ function isKey($value, $object = []): bool
         return false;
     }
 
-    if (\is_scalar($value)) {
+    if (\is_numeric($value)) {
         return true;
     }
 
     return \preg_match(reIsPlainProp, $value) || !\preg_match(reIsDeepProp, $value) || (null !== $object && isset(((object) $object)->$value));
-}
\ No newline at end of file
+}
diff --git a/src/internal/memoizeCapped.php b/src/internal/memoizeCapped.php
new file mode 100644
index 0000000..0eb18d0
--- /dev/null
+++ b/src/internal/memoizeCapped.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+use function _\memoize;
+
+function memoizeCapped(callable $func)
+{
+    $MaxMemoizeSize = 500;
+    $result = memoize($func, function ($key) use ($MaxMemoizeSize) {
+        if ($this->cache->getSize() === $MaxMemoizeSize) {
+            $this->cache->clear();
+        }
+
+        return $key;
+    });
+
+    return $result;
+}
diff --git a/src/internal/overRest.php b/src/internal/overRest.php
new file mode 100644
index 0000000..a17be23
--- /dev/null
+++ b/src/internal/overRest.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function overRest(callable $func, $start, callable $transform): callable
+{
+    $parameters = (new \ReflectionFunction($func))->getNumberOfParameters();
+    $start = max($start ?? $parameters - 1, 0);
+
+    return function () use ($func, $start, $transform) {
+        $args = \func_get_args();
+        $index = -1;
+        $length = \max(\count($args) - $start, 0);
+        $array = [];
+
+        while (++$index < $length) {
+            $array[$index] = $args[$start + $index];
+        }
+        $index = -1;
+        $otherArgs = [];
+        while (++$index < $start) {
+            $otherArgs[$index] = $args[$index];
+        }
+        $otherArgs[$start] = $transform($array);
+
+        return $func(...$otherArgs);
+    };
+}
diff --git a/src/internal/parent.php b/src/internal/parent.php
new file mode 100644
index 0000000..49b3d78
--- /dev/null
+++ b/src/internal/parent.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+function parent($object, $path)
+{
+    return count($path) < 2 ? $object : null;
+}
diff --git a/src/internal/shortOut.php b/src/internal/shortOut.php
new file mode 100644
index 0000000..826ac6b
--- /dev/null
+++ b/src/internal/shortOut.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+const HOT_COUNT = 800;
+const HOT_SPAN = 16;
+
+/**
+ * Creates a function that'll short out and invoke `identity` instead
+ * of `func` when it's called `HOT_COUNT` or more times in `HOT_SPAN`
+ * milliseconds.
+ *
+ * @private
+ *
+ * @param callable $func The function to restrict.
+ *
+ * @return callable Returns the new shortable function.
+ */
+function shortOut(callable $func): callable
+{
+    $count = 0;
+    $lastCalled = 0;
+
+    return function () use ($func, &$count, &$lastCalled) {
+        $stamp = microtime(true);
+        $remaining = HOT_SPAN - ($stamp - $lastCalled);
+
+        $lastCalled = $stamp;
+        if ($remaining > 0) {
+            if (++$count >= HOT_COUNT) {
+                return func_get_arg(0);
+            }
+        } else {
+            $count = 0;
+        }
+
+        return $func(...func_get_args());
+    };
+}
diff --git a/src/internal/stringSize.php b/src/internal/stringSize.php
index 4957576..10efb63 100644
--- a/src/internal/stringSize.php
+++ b/src/internal/stringSize.php
@@ -15,9 +15,12 @@
  * Gets the number of symbols in `string`.
  *
  * @private
- * @param {string} string The string to inspect.
- * @returns {number} Returns the string size.
+ *
+ * @param string $string The string to inspect.
+ *
+ * @return int Returns the string size.
  */
-function stringSize(string $string) {
+function stringSize(string $string): int
+{
     return hasUnicode($string) ? unicodeSize($string) : \strlen($string);
-}
\ No newline at end of file
+}
diff --git a/src/internal/stringToArray.php b/src/internal/stringToArray.php
index f451361..ff9458f 100644
--- a/src/internal/stringToArray.php
+++ b/src/internal/stringToArray.php
@@ -18,9 +18,9 @@
  *
  * @param string $string The string to convert.
  *
- * @returns array Returns the converted array.
+ * @return array Returns the converted array.
  */
 function stringToArray(string $string): array
 {
     return hasUnicode($string) ? unicodeToArray($string) : \str_split($string);
-}
\ No newline at end of file
+}
diff --git a/src/internal/stringToPath.php b/src/internal/stringToPath.php
new file mode 100644
index 0000000..d2d8b39
--- /dev/null
+++ b/src/internal/stringToPath.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2018
+ */
+
+namespace _\internal;
+
+const reLeadingDot = '/^\./';
+const rePropName = '#[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["\'])((?:(?!\2)[^\\\\]|\\.)*?)\2)\]|(?=(?:\.|\[\])(?:\.|\[\]|$))#';
+
+/** Used to match backslashes in property paths. */
+const reEscapeChar = '/\\(\\)?/g';
+
+function stringToPath(...$args)
+{
+    return memoizeCapped(function ($string) {
+        $result = [];
+        if (\preg_match(reLeadingDot, $string)) {
+            $result[] = '';
+        }
+
+        \preg_match_all(rePropName, $string, $matches, PREG_SPLIT_DELIM_CAPTURE);
+
+        foreach ($matches as $match) {
+            $result[] = $match[1] ?? $match[0];
+        }
+
+        return $result;
+    })(...$args);
+}
diff --git a/src/internal/toKey.php b/src/internal/toKey.php
index e44522f..d7a8117 100644
--- a/src/internal/toKey.php
+++ b/src/internal/toKey.php
@@ -14,9 +14,9 @@
 /**
  * Converts `value` to a string key if it's not a string.
  *
- * @param mixed value The value to inspect.
+ * @param mixed $value The value to inspect.
  *
- * @returns string Returns the key.
+ * @return string Returns the key.
  */
 function toKey($value): string
 {
@@ -27,4 +27,4 @@ function toKey($value): string
     $result = (string) $value;
 
     return ('0' === $result && (1 / $value) === -INF) ? '-0' : $result;
-}
\ No newline at end of file
+}
diff --git a/src/internal/unicode.php b/src/internal/unicode.php
index eee0dc8..dd371ba 100644
--- a/src/internal/unicode.php
+++ b/src/internal/unicode.php
@@ -60,4 +60,4 @@
 define('rsSymbol', '(?:'.implode('|', [rsNonAstralCombo, rsCombo, rsRegional, rsSurrPair, rsAstral]).')');
 
 /** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
-const reUnicode = rsFitz.'(?='.rsFitz.')|'.rsSymbol.rsSeq;
\ No newline at end of file
+const reUnicode = rsFitz.'(?='.rsFitz.')|'.rsSymbol.rsSeq;
diff --git a/src/internal/unicodeSize.php b/src/internal/unicodeSize.php
index af7f993..47ed627 100644
--- a/src/internal/unicodeSize.php
+++ b/src/internal/unicodeSize.php
@@ -18,9 +18,9 @@
  *
  * @param string $string The string inspect.
  *
- * @returns int Returns the string size.
+ * @return int Returns the string size.
  */
-function unicodeSize($string): int
+function unicodeSize(string $string): int
 {
-    return \preg_match_all(reUnicode, $string);
-}
\ No newline at end of file
+    return \preg_match_all(reUnicode, $string) ?: 0;
+}
diff --git a/src/internal/unicodeToArray.php b/src/internal/unicodeToArray.php
index bcf5f3e..b63030f 100644
--- a/src/internal/unicodeToArray.php
+++ b/src/internal/unicodeToArray.php
@@ -18,7 +18,7 @@
  *
  * @param string $string The string to convert.
  *
- * @returns array Returns the converted array.
+ * @return array Returns the converted array.
  */
 function unicodeToArray(string $string): array
 {
diff --git a/src/internal/unicodeWords.php b/src/internal/unicodeWords.php
index 25602f6..9f2a0c3 100644
--- a/src/internal/unicodeWords.php
+++ b/src/internal/unicodeWords.php
@@ -16,10 +16,11 @@
  *
  * @private
  *
- * @param {string} The string to inspect.
- * @returns {Array} Returns the words of `string`.
+ * @param string $string The string to inspect.
+ *
+ * @return array Returns the words of `string`.
  */
-function unicodeWords(string $string)
+function unicodeWords(string $string): array
 {
     $regex = '#'.\implode('|', [
             rsUpper.'?'.rsLower.'+'.rsOptContrLower.'(?='.\implode('|', [rsBreak, rsUpper, '$']).')',
@@ -37,4 +38,4 @@ function unicodeWords(string $string)
     }
 
     return [];
-}
\ No newline at end of file
+}
diff --git a/tests/Array/ChunkTest.php b/tests/Array/ChunkTest.php
index 36ae165..7eec8b4 100644
--- a/tests/Array/ChunkTest.php
+++ b/tests/Array/ChunkTest.php
@@ -23,4 +23,4 @@ public function testChunk()
         $this->assertSame([], chunk([], -12));
         $this->assertSame([], chunk([], 22));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/CompactTest.php b/tests/Array/CompactTest.php
index 0ff804d..578b600 100644
--- a/tests/Array/CompactTest.php
+++ b/tests/Array/CompactTest.php
@@ -20,4 +20,4 @@ public function testChunk()
         $this->assertSame([], compact([]));
         $this->assertSame([], compact(null));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/ConcatTest.php b/tests/Array/ConcatTest.php
index e601367..672945e 100644
--- a/tests/Array/ConcatTest.php
+++ b/tests/Array/ConcatTest.php
@@ -22,4 +22,4 @@ public function testChunk()
         $this->assertSame([1, 2, 3, [4]], $other);
         $this->assertSame([1], $array); // Ensure original array doesn't get changed
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/DifferenceByTest.php b/tests/Array/DifferenceByTest.php
index 32acd27..ac13c82 100644
--- a/tests/Array/DifferenceByTest.php
+++ b/tests/Array/DifferenceByTest.php
@@ -14,10 +14,10 @@
 
 class DifferenceByTest extends TestCase
 {
-    public function testChunk()
+    public function testDifferenceBy()
     {
         $this->assertSame([], differenceBy([]));
         $this->assertSame([1, 2], differenceBy([1, 2], [3, 4]));
         $this->assertSame([1.2], differenceBy([2.1, 1.2], [2.3, 3.4], 'floor'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/DifferenceTest.php b/tests/Array/DifferenceTest.php
index 149033c..5e74f5e 100644
--- a/tests/Array/DifferenceTest.php
+++ b/tests/Array/DifferenceTest.php
@@ -18,4 +18,4 @@ public function testChunk()
     {
         $this->assertSame([1], difference([2, 1], [2, 3]));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/DifferenceWithTest.php b/tests/Array/DifferenceWithTest.php
index 89bf204..75e3032 100644
--- a/tests/Array/DifferenceWithTest.php
+++ b/tests/Array/DifferenceWithTest.php
@@ -22,4 +22,4 @@ public function testDifferenceWith()
         $this->assertSame([], differenceWith([]));
         $this->assertSame([1, 2], differenceWith([1, 2], [3, 4]));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/DropRightTest.php b/tests/Array/DropRightTest.php
index b0a6f14..d94d99c 100644
--- a/tests/Array/DropRightTest.php
+++ b/tests/Array/DropRightTest.php
@@ -21,4 +21,4 @@ public function testDropRight()
         $this->assertSame([], dropRight([1, 2, 3], 5));
         $this->assertSame([1, 2, 3], dropRight([1, 2, 3], 0));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/DropRightWhileTest.php b/tests/Array/DropRightWhileTest.php
index 2ded769..f0ced1c 100644
--- a/tests/Array/DropRightWhileTest.php
+++ b/tests/Array/DropRightWhileTest.php
@@ -22,6 +22,8 @@ public function testDropRightWhile()
             ['user' => 'pebbles', 'active' => true],
         ];
 
-        $this->assertSame([[ 'user' => 'barney',  'active' => false ]], dropRightWhile($users, function($user) { return $user['active']; }));
+        $this->assertSame([[ 'user' => 'barney',  'active' => false ]], dropRightWhile($users, function ($user) {
+            return $user['active'];
+        }));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/DropTest.php b/tests/Array/DropTest.php
index 48a94d1..67320d9 100644
--- a/tests/Array/DropTest.php
+++ b/tests/Array/DropTest.php
@@ -21,4 +21,4 @@ public function testDrop()
         $this->assertSame([], drop([1, 2, 3], 5));
         $this->assertSame([1, 2, 3], drop([1, 2, 3], 0));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/DropWhileTest.php b/tests/Array/DropWhileTest.php
index bae78bb..50bef5a 100644
--- a/tests/Array/DropWhileTest.php
+++ b/tests/Array/DropWhileTest.php
@@ -22,6 +22,28 @@ public function testDropWhile()
             ['user' => 'pebbles', 'active' => false],
         ];
 
-        $this->assertSame([['user' => 'pebbles', 'active' => false]], dropWhile($users, function ($user) { return $user['active']; }));
+        $this->assertSame([['user' => 'pebbles', 'active' => false]], dropWhile($users, function ($user) {
+            return $user['active'];
+        }));
+    
+        $lines = [
+            'Processing report:',
+            'Processed: 1',
+            'Successful: 1',
+            '',
+            '',
+        ];
+
+        $lines = dropWhile($lines, static function ($x) {
+            return trim((string) $x) !== '';
+        });
+
+        self::assertEquals(['', ''], $lines);
+
+        $lines = dropWhile($lines, static function ($x) {
+            return trim((string) $x) === '';
+        });
+
+        self::assertEmpty($lines);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/FindIndexTest.php b/tests/Array/FindIndexTest.php
index df0d520..420032d 100644
--- a/tests/Array/FindIndexTest.php
+++ b/tests/Array/FindIndexTest.php
@@ -22,7 +22,9 @@ public function testFindIndex()
             ['user' => 'pebbles', 'active' => true],
         ];
 
-        $this->assertSame(2, findIndex($users, function ($user) { return $user['user'] === 'pebbles'; }));
+        $this->assertSame(2, findIndex($users, function ($user) {
+            return $user['user'] === 'pebbles';
+        }));
         $this->assertSame(1, findIndex($users, ['user' => 'fred', 'active' => false]));
         $this->assertSame(0, findIndex($users, ['active', false]));
         $this->assertSame(2, findIndex($users, 'active'));
@@ -30,4 +32,4 @@ public function testFindIndex()
         $this->assertSame(2, findIndex($users, 'active', -2));
         $this->assertSame(-1, findIndex($users, 'nothing'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/FindLastIndexTest.php b/tests/Array/FindLastIndexTest.php
index 61aacb7..df82393 100644
--- a/tests/Array/FindLastIndexTest.php
+++ b/tests/Array/FindLastIndexTest.php
@@ -22,8 +22,12 @@ public function testFindLastIndex()
             ['user' => 'pebbles', 'active' => false],
         ];
 
-        $this->assertSame(2, findLastIndex($users, function ($user) { return $user['user'] === 'pebbles'; }));
-        $this->assertSame(-1, findLastIndex($users, function ($user) { return $user['user'] === 'wilma'; }));
+        $this->assertSame(2, findLastIndex($users, function ($user) {
+            return $user['user'] === 'pebbles';
+        }));
+        $this->assertSame(-1, findLastIndex($users, function ($user) {
+            return $user['user'] === 'wilma';
+        }));
         $this->assertSame(1, findLastIndex($users, ['user' => 'fred'], -1));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/FlattenDeepTest.php b/tests/Array/FlattenDeepTest.php
index 126d9f8..028529d 100644
--- a/tests/Array/FlattenDeepTest.php
+++ b/tests/Array/FlattenDeepTest.php
@@ -18,4 +18,4 @@ public function testFlattenDeep()
     {
         $this->assertSame([1, 2, 3, 4, 5], flattenDeep([1, [2, [3, [4]], 5]]));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/FlattenDepthTest.php b/tests/Array/FlattenDepthTest.php
index d8a98e0..d796d64 100644
--- a/tests/Array/FlattenDepthTest.php
+++ b/tests/Array/FlattenDepthTest.php
@@ -20,4 +20,4 @@ public function testFlattenDepth()
         $this->assertSame([1, 2, [3, [4]], 5], flattenDepth($array, 1));
         $this->assertSame([1, 2, 3, [4], 5], flattenDepth($array, 2));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/FlattenTest.php b/tests/Array/FlattenTest.php
index bf972c4..3c28d78 100644
--- a/tests/Array/FlattenTest.php
+++ b/tests/Array/FlattenTest.php
@@ -17,5 +17,7 @@ class FlattenTest extends TestCase
     public function testFlatten()
     {
         $this->assertSame([1, 2, [3, [4]], 5], flatten([1, [2, [3, [4]], 5]]));
+
+        $this->assertSame([1, 2, 3, 4, 5, 6], flatten([[1, 2, 3], [], [4, 5, 6]]));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/FromPairsTest.php b/tests/Array/FromPairsTest.php
index abb09c2..726db51 100644
--- a/tests/Array/FromPairsTest.php
+++ b/tests/Array/FromPairsTest.php
@@ -19,4 +19,4 @@ public function testFromPairs()
         $this->assertEquals((object) ['a' => 1, 'b' => 2], fromPairs([['a', 1], ['b', 2]]));
         $this->assertEquals(new \stdClass(), fromPairs([]));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/HeadTest.php b/tests/Array/HeadTest.php
index bf2ed5f..6e6a54c 100644
--- a/tests/Array/HeadTest.php
+++ b/tests/Array/HeadTest.php
@@ -21,4 +21,4 @@ public function testHead()
         $this->assertSame(null, head([]));
         $this->assertSame(1, first([1, 2, 3])); // Test the alias
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/IndexOfTest.php b/tests/Array/IndexOfTest.php
index 203de6b..b93c795 100644
--- a/tests/Array/IndexOfTest.php
+++ b/tests/Array/IndexOfTest.php
@@ -20,4 +20,4 @@ public function testIndexOf()
         $this->assertSame(3, indexOf([1, 2, 1, 2], 2, 2));
         $this->assertSame(3, indexOf([1, 2, 1, 2], 2, -1));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/InitialTest.php b/tests/Array/InitialTest.php
index 0ea8860..8aec608 100644
--- a/tests/Array/InitialTest.php
+++ b/tests/Array/InitialTest.php
@@ -18,4 +18,4 @@ public function testInitial()
     {
         $this->assertSame([1, 2], initial([1, 2, 3]));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/IntersectionByTest.php b/tests/Array/IntersectionByTest.php
index 34c4cc0..f0bb695 100644
--- a/tests/Array/IntersectionByTest.php
+++ b/tests/Array/IntersectionByTest.php
@@ -19,4 +19,4 @@ public function testIntersectionBy()
         $this->assertSame([2.1], intersectionBy([2.1, 1.2], [2.3, 3.4], 'floor'));
         $this->assertSame([['x' => 1]], intersectionBy([['x' => 1]], [['x' => 2], ['x' => 1]], 'x'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/IntersectionTest.php b/tests/Array/IntersectionTest.php
index 7f89c8b..f8a9448 100644
--- a/tests/Array/IntersectionTest.php
+++ b/tests/Array/IntersectionTest.php
@@ -18,4 +18,4 @@ public function testIntersection()
     {
         $this->assertSame([2], intersection([2, 1], [2, 3]));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/IntersectionWithTest.php b/tests/Array/IntersectionWithTest.php
index fa6d258..d8da175 100644
--- a/tests/Array/IntersectionWithTest.php
+++ b/tests/Array/IntersectionWithTest.php
@@ -19,7 +19,7 @@ public function testIntersectionWith()
         $objects = [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1]];
         $others = [['x' => 1, 'y' => 1], ['x' => 1, 'y' => 2]];
 
-        $this->assertSame([['x' => 1, 'y' => 2]], intersectionWith($objects, $others, '_::isEqual'));
+        $this->assertSame([['x' => 1, 'y' => 2]], intersectionWith($objects, $others, '_\isEqual'));
         $this->assertSame([['x' => 1, 'y' => 2]], intersectionWith($objects, $others));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/LastIndexOfTest.php b/tests/Array/LastIndexOfTest.php
index 09795f1..56da38a 100644
--- a/tests/Array/LastIndexOfTest.php
+++ b/tests/Array/LastIndexOfTest.php
@@ -20,4 +20,4 @@ public function testLastIndexOf()
         $this->assertSame(1, lastIndexOf([1, 2, 1, 2], 2, 2));
         $this->assertSame(-1, lastIndexOf([1, 2, 1, 2], 12));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/LastTest.php b/tests/Array/LastTest.php
index c69020a..e41aa93 100644
--- a/tests/Array/LastTest.php
+++ b/tests/Array/LastTest.php
@@ -18,4 +18,4 @@ public function testLast()
     {
         $this->assertSame(3, last([1, 2, 3]));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/NthTest.php b/tests/Array/NthTest.php
index e1978be..725f0d2 100644
--- a/tests/Array/NthTest.php
+++ b/tests/Array/NthTest.php
@@ -21,4 +21,4 @@ public function testNth()
         $this->assertSame('c', nth($array, -2));
         $this->assertSame(null, nth($array, 12));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/PullAllByTest.php b/tests/Array/PullAllByTest.php
index 3714802..6682e3b 100644
--- a/tests/Array/PullAllByTest.php
+++ b/tests/Array/PullAllByTest.php
@@ -20,4 +20,4 @@ public function testPullAllBy()
         pullAllBy($array, [[ 'x' => 1 ], [ 'x' => 3 ]], 'x');
         $this->assertSame([[ 'x' => 2 ]], $array);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/PullAllTest.php b/tests/Array/PullAllTest.php
index cfec891..34aab23 100644
--- a/tests/Array/PullAllTest.php
+++ b/tests/Array/PullAllTest.php
@@ -20,4 +20,4 @@ public function testPullAll()
         pullAll($array, ['a', 'c']);
         $this->assertSame(['b', 'b'], $array);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/PullAllWithTest.php b/tests/Array/PullAllWithTest.php
index cbabe04..7a0a4c1 100644
--- a/tests/Array/PullAllWithTest.php
+++ b/tests/Array/PullAllWithTest.php
@@ -20,4 +20,4 @@ public function testPullAllWith()
         pullAllWith($array, [['x' => 3, 'y' => 4]], '_\isEqual');
         $this->assertSame([['x' => 1, 'y' => 2], ['x' => 5, 'y' => 6]], $array);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/PullAtTest.php b/tests/Array/PullAtTest.php
index 4961244..14be4da 100644
--- a/tests/Array/PullAtTest.php
+++ b/tests/Array/PullAtTest.php
@@ -21,4 +21,4 @@ public function testPullAt()
         $this->assertSame(['a', 'c'], $array);
         $this->assertSame(['b', 'd'], $pulled);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/PullTest.php b/tests/Array/PullTest.php
index 725f088..c3bda88 100644
--- a/tests/Array/PullTest.php
+++ b/tests/Array/PullTest.php
@@ -21,4 +21,4 @@ public function testPull()
 
         $this->assertSame(['b', 'b'], $array);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/RemoveTest.php b/tests/Array/RemoveTest.php
index cfcd2a9..fa60b1a 100644
--- a/tests/Array/RemoveTest.php
+++ b/tests/Array/RemoveTest.php
@@ -17,8 +17,10 @@ class RemoveTest extends TestCase
     public function testRemove()
     {
         $array = [1, 2, 3, 4];
-        $evens = remove($array, function ($n) { return $n % 2 === 0; });
+        $evens = remove($array, function ($n) {
+            return $n % 2 === 0;
+        });
         $this->assertSame([1, 3], $array);
         $this->assertSame([2, 4], $evens);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/SliceTest.php b/tests/Array/SliceTest.php
index 3bc465f..0272dc1 100644
--- a/tests/Array/SliceTest.php
+++ b/tests/Array/SliceTest.php
@@ -19,4 +19,4 @@ public function testSlice()
         $array = ['a', 'b', 'c', 'd'];
         $this->assertSame(['c', 'd'], slice($array, 2));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Array/TailTest.php b/tests/Array/TailTest.php
new file mode 100644
index 0000000..13da9de
--- /dev/null
+++ b/tests/Array/TailTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\tail;
+use PHPUnit\Framework\TestCase;
+
+class TailTest extends TestCase
+{
+    public function testTail()
+    {
+        $this->assertSame([2, 3], tail([1, 2, 3]));
+    }
+}
diff --git a/tests/Array/TakeRightTest.php b/tests/Array/TakeRightTest.php
new file mode 100644
index 0000000..a749129
--- /dev/null
+++ b/tests/Array/TakeRightTest.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\takeRight;
+
+class TakeRightTest extends TestCase
+{
+    public function testTakeRight()
+    {
+        $this->assertSame([3], takeRight([1, 2, 3]));
+        $this->assertSame([2, 3], takeRight([1, 2, 3], 2));
+        $this->assertSame([1, 2, 3], takeRight([1, 2, 3], 5));
+        $this->assertSame([], takeRight([1, 2, 3], 0));
+    }
+}
diff --git a/tests/Array/TakeRightWhileTest.php b/tests/Array/TakeRightWhileTest.php
new file mode 100644
index 0000000..7aea59e
--- /dev/null
+++ b/tests/Array/TakeRightWhileTest.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\takeRightWhile;
+
+class TakeRightWhileTest extends TestCase
+{
+    public function testTakeRightWhile()
+    {
+        $users = [
+            ['user' => 'barney', 'active' => false],
+            ['user' => 'fred', 'active' => true],
+            ['user' => 'pebbles', 'active' => true],
+        ];
+
+        $this->assertSame([['user' => 'fred', 'active' => true], ['user' => 'pebbles', 'active' => true]], takeRightWhile($users, function ($value) {
+            return $value['active'];
+        }));
+    }
+}
diff --git a/tests/Array/TakeTest.php b/tests/Array/TakeTest.php
new file mode 100644
index 0000000..8fda463
--- /dev/null
+++ b/tests/Array/TakeTest.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\take;
+
+class TakeTest extends TestCase
+{
+    public function testTake()
+    {
+        $this->assertSame([1], take([1, 2, 3]));
+        $this->assertSame([1, 2], take([1, 2, 3], 2));
+        $this->assertSame([1, 2, 3], take([1, 2, 3], 5));
+        $this->assertSame([], take([1, 2, 3], 0));
+    }
+}
diff --git a/tests/Array/TakeWhileTest.php b/tests/Array/TakeWhileTest.php
new file mode 100644
index 0000000..2e05a33
--- /dev/null
+++ b/tests/Array/TakeWhileTest.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\takeWhile;
+
+class TakeWhileTest extends TestCase
+{
+    public function testTakeWhile()
+    {
+        $users = [
+            ['user' => 'barney', 'active' => true],
+            ['user' => 'fred', 'active' => true],
+            ['user' => 'pebbles', 'active' => false],
+        ];
+
+        $this->assertSame([['user' => 'barney', 'active' => true], ['user' => 'fred', 'active' => true]], takeWhile($users, function ($value) {
+            return $value['active'];
+        }));
+    }
+}
diff --git a/tests/Array/UnionByTest.php b/tests/Array/UnionByTest.php
new file mode 100644
index 0000000..0dff8c9
--- /dev/null
+++ b/tests/Array/UnionByTest.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\unionBy;
+use PHPUnit\Framework\TestCase;
+
+class UnionByTest extends TestCase
+{
+    public function testUnionBy()
+    {
+        $this->assertSame([2.1, 1.2], unionBy([2.1], [1.2, 2.3], 'floor'));
+        $this->assertSame([['x' => 1], ['x' => 2]], unionBy([['x' => 1]], [['x' => 2], ['x' => 1]], 'x'));
+    }
+}
diff --git a/tests/Array/UnionTest.php b/tests/Array/UnionTest.php
new file mode 100644
index 0000000..2d0a80b
--- /dev/null
+++ b/tests/Array/UnionTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\union;
+use PHPUnit\Framework\TestCase;
+
+class UnionTest extends TestCase
+{
+    public function testUnion()
+    {
+        $this->assertSame([2, 1], union([2], [1, 2]));
+    }
+}
diff --git a/tests/Array/UnionWithTest.php b/tests/Array/UnionWithTest.php
new file mode 100644
index 0000000..a95d2ee
--- /dev/null
+++ b/tests/Array/UnionWithTest.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\unionWith;
+
+class UnionWithTest extends TestCase
+{
+    public function testUnionWith()
+    {
+        $objects = [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1]];
+        $others = [['x' => 1, 'y' => 1], ['x' => 1, 'y' => 2]];
+
+        $this->assertSame([['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1], ['x' => 1, 'y' => 1]], unionWith($objects, $others, '_::isEqual'));
+    }
+}
diff --git a/tests/Array/UniqByTest.php b/tests/Array/UniqByTest.php
new file mode 100644
index 0000000..7ee23b4
--- /dev/null
+++ b/tests/Array/UniqByTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\uniqBy;
+use PHPUnit\Framework\TestCase;
+
+class UniqByTest extends TestCase
+{
+    public function testUniqBy()
+    {
+        $this->assertSame([2.1, 1.2], uniqBy([2.1, 1.2, 2.3], 'floor'));
+    }
+}
diff --git a/tests/Array/UniqTest.php b/tests/Array/UniqTest.php
new file mode 100644
index 0000000..da47eca
--- /dev/null
+++ b/tests/Array/UniqTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\uniq;
+use PHPUnit\Framework\TestCase;
+
+class UniqTest extends TestCase
+{
+    public function testUniq()
+    {
+        $this->assertSame([2, 1], uniq([2, 1, 2]));
+    }
+}
diff --git a/tests/Array/UniqWithTest.php b/tests/Array/UniqWithTest.php
new file mode 100644
index 0000000..65b254b
--- /dev/null
+++ b/tests/Array/UniqWithTest.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\uniqWith;
+
+class UniqWithTest extends TestCase
+{
+    public function testUniqWith()
+    {
+        $objects = [['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1], ['x' => 1, 'y' => 2]];
+        $this->assertSame([['x' => 1, 'y' => 2], ['x' => 2, 'y' => 1]], uniqWith($objects, '_::isEqual'));
+    }
+}
diff --git a/tests/Array/UnzipTest.php b/tests/Array/UnzipTest.php
new file mode 100644
index 0000000..d376e53
--- /dev/null
+++ b/tests/Array/UnzipTest.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\unzip;
+
+class UnzipTest extends TestCase
+{
+    public function testUnzip()
+    {
+        $zipped = [['a', 1, true], ['b', 2, false]];
+        $this->assertSame([['a', 'b'], [1, 2], [true, false]], unzip($zipped));
+    }
+}
diff --git a/tests/Array/UnzipWithTest.php b/tests/Array/UnzipWithTest.php
new file mode 100644
index 0000000..512f1dc
--- /dev/null
+++ b/tests/Array/UnzipWithTest.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\unzipWith;
+use PHPUnit\Framework\TestCase;
+
+class UnzipWithTest extends TestCase
+{
+    public function testUnzipWith()
+    {
+        $zipped = [[1, 10, 100], [2, 20, 200]];
+        $this->assertSame([3, 30, 300], unzipWith($zipped, '_::add'));
+    }
+}
diff --git a/tests/Array/WithoutTest.php b/tests/Array/WithoutTest.php
new file mode 100644
index 0000000..935d2e7
--- /dev/null
+++ b/tests/Array/WithoutTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\without;
+
+class WithoutTest extends TestCase
+{
+    public function testWithout()
+    {
+        $this->assertSame([3], without([2, 1, 2, 3], 1, 2));
+    }
+}
diff --git a/tests/Array/ZipObjectDeepTest.php b/tests/Array/ZipObjectDeepTest.php
new file mode 100644
index 0000000..7bc582b
--- /dev/null
+++ b/tests/Array/ZipObjectDeepTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\zipObjectDeep;
+
+class ZipObjectDeepTest extends TestCase
+{
+    public function testZipObjectDeep()
+    {
+        $this->assertEquals((object) ['a' => (object) ['b' => [(object) ['c' => 1], (object) ['d' => 2]]]], zipObjectDeep(['a.b[0].c', 'a.b[1].d'], [1, 2]));
+    }
+}
diff --git a/tests/Array/ZipObjectTest.php b/tests/Array/ZipObjectTest.php
new file mode 100644
index 0000000..b4ac506
--- /dev/null
+++ b/tests/Array/ZipObjectTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\zipObject;
+use PHPUnit\Framework\TestCase;
+
+class ZipObjectTest extends TestCase
+{
+    public function testZipObject()
+    {
+        $this->assertEquals((object) ['a' => 1, 'b' => 2], zipObject(['a', 'b'], [1, 2]));
+    }
+}
diff --git a/tests/Array/ZipTest.php b/tests/Array/ZipTest.php
new file mode 100644
index 0000000..18243cd
--- /dev/null
+++ b/tests/Array/ZipTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\zip;
+
+class ZipTest extends TestCase
+{
+    public function testZip()
+    {
+        $this->assertSame([['a', 1, true], ['b', 2, false]], zip(['a', 'b'], [1, 2], [true, false]));
+    }
+}
diff --git a/tests/Array/ZipWithTest.php b/tests/Array/ZipWithTest.php
new file mode 100644
index 0000000..a3a06f3
--- /dev/null
+++ b/tests/Array/ZipWithTest.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\zipWith;
+use PHPUnit\Framework\TestCase;
+
+class ZipWithTest extends TestCase
+{
+    public function testZipWith()
+    {
+        $this->assertSame([111, 222], zipWith([1, 2], [10, 20], [100, 200], function ($a, $b, $c) {
+            return $a + $b + $c;
+        }));
+    }
+}
diff --git a/tests/Collection/CountByTest.php b/tests/Collection/CountByTest.php
new file mode 100644
index 0000000..0f7d329
--- /dev/null
+++ b/tests/Collection/CountByTest.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\countBy;
+use PHPUnit\Framework\TestCase;
+
+class CountByTest extends TestCase
+{
+    public function testCountBy()
+    {
+        $this->assertSame(['6' => 2, '4' => 1], countBy([6.1, 4.2, 6.3], 'floor'));
+        $this->assertSame(['3' => 2, '5' => 1], countBy(['one', 'two', 'three'], 'strlen'));
+    }
+}
diff --git a/tests/Collection/EachRightTest.php b/tests/Collection/EachRightTest.php
new file mode 100644
index 0000000..ee68693
--- /dev/null
+++ b/tests/Collection/EachRightTest.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\eachRight;
+use PHPUnit\Framework\TestCase;
+
+class EachRightTest extends TestCase
+{
+    public function testForEachRight()
+    {
+        $test = [];
+        eachRight([1, 2], function ($value) use (&$test) {
+            $test[$value] = true;
+        });
+        $this->assertSame([2 => true, 1 => true], $test);
+
+        $test = [];
+        eachRight((object) ['a' => 1, 'b' => 2], function ($value) use (&$test) {
+            $test[$value] = true;
+        });
+        $this->assertSame([2 => true, 1 => true], $test);
+    }
+}
diff --git a/tests/Collection/EachTest.php b/tests/Collection/EachTest.php
index 22507cd..bcd1340 100644
--- a/tests/Collection/EachTest.php
+++ b/tests/Collection/EachTest.php
@@ -19,11 +19,15 @@ public function testEach()
         $testFunc = new \stdClass();
 
         $testFunc->total = 0;
-        each([1, 2], function ($value) use ($testFunc) { $testFunc->total += $value; });
+        each([1, 2], function ($value) use ($testFunc) {
+            $testFunc->total += $value;
+        });
         $this->assertSame(3, $testFunc->total);
 
         $testFunc->total = 0;
-        each((object) ['a' => 1, 'b' => 2], function ($value) use ($testFunc) { $testFunc->total += $value; });
+        each((object) ['a' => 1, 'b' => 2], function ($value) use ($testFunc) {
+            $testFunc->total += $value;
+        });
         $this->assertSame(3, $testFunc->total);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Collection/EveryTest.php b/tests/Collection/EveryTest.php
new file mode 100644
index 0000000..bb118eb
--- /dev/null
+++ b/tests/Collection/EveryTest.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\every;
+
+class EveryTest extends TestCase
+{
+    public function testEvery()
+    {
+        $this->assertFalse(every([true, 1, null, 'yes'], function ($value) {
+            return is_bool($value);
+        }));
+
+        $users = [
+            ['user' => 'barney', 'age' => 36, 'active' => false],
+            ['user' => 'fred', 'age' => 40, 'active' => false],
+        ];
+
+        // The `matches` iteratee shorthand.
+        $this->assertFalse(every($users, ['user' => 'barney', 'active' => false]));
+
+        // The `matchesProperty` iteratee shorthand.
+        $this->assertTrue(every($users, ['active', false]));
+
+        // The `property` iteratee shorthand.
+        $this->assertFalse(every($users, 'active'));
+    }
+}
diff --git a/tests/Collection/FilterTest.php b/tests/Collection/FilterTest.php
new file mode 100644
index 0000000..0adcc8c
--- /dev/null
+++ b/tests/Collection/FilterTest.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\filter;
+
+class FilterTest extends TestCase
+{
+    public function testFilter()
+    {
+        $users = [
+            ['user' => 'barney', 'age' => 36, 'active' => true],
+            ['user' => 'fred', 'age' => 40, 'active' => false],
+        ];
+
+        $this->assertSame([['user' => 'fred', 'age' => 40, 'active' => false]], filter($users, function ($o) {
+            return !$o['active'];
+        }));
+
+        // The `matches` iteratee shorthand.
+        $this->assertSame([['user' => 'barney', 'age' => 36, 'active' => true]], filter($users, ['age' => 36, 'active' => true]));
+
+        // The `matchesProperty` iteratee shorthand.
+        $this->assertSame([['user' => 'fred', 'age' => 40, 'active' => false]], filter($users, ['active', false]));
+
+        // The `property` iteratee shorthand.
+        $this->assertSame([['user' => 'barney', 'age' => 36, 'active' => true]], filter($users, 'active'));
+    }
+}
diff --git a/tests/Collection/FindLastTest.php b/tests/Collection/FindLastTest.php
new file mode 100644
index 0000000..f018a06
--- /dev/null
+++ b/tests/Collection/FindLastTest.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\findLast;
+
+class FindLastTest extends TestCase
+{
+    public function testFindLast()
+    {
+        $this->assertSame(3, findLast([1, 2, 3, 4], function ($n) {
+            return $n % 2 == 1;
+        }));
+    }
+}
diff --git a/tests/Collection/FindTest.php b/tests/Collection/FindTest.php
new file mode 100644
index 0000000..7d28e6d
--- /dev/null
+++ b/tests/Collection/FindTest.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\find;
+
+class FindTest extends TestCase
+{
+    public function testFind()
+    {
+        $users = [
+            ['user' => 'barney', 'age' => 36, 'active' => true],
+            ['user' => 'fred', 'age' => 40, 'active' => false],
+            ['user' => 'pebbles', 'age' => 1, 'active' => true],
+        ];
+
+        $this->assertSame(['user' => 'barney', 'age' => 36, 'active' => true], find($users, function ($o) {
+            return $o['age'] < 40;
+        }));
+
+        // The `matches` iteratee shorthand.
+        $this->assertSame(['user' => 'pebbles', 'age' => 1, 'active' => true], find($users, ['age' => 1, 'active' => true]));
+
+        // The `matchesProperty` iteratee shorthand.
+        $this->assertSame(['user' => 'fred', 'age' => 40, 'active' => false], find($users, ['active', false]));
+
+        // The `property` iteratee shorthand.
+        $this->assertSame(['user' => 'barney', 'age' => 36, 'active' => true], find($users, 'active'));
+    }
+}
diff --git a/tests/Collection/FlatMapDeepTest.php b/tests/Collection/FlatMapDeepTest.php
new file mode 100644
index 0000000..5a99382
--- /dev/null
+++ b/tests/Collection/FlatMapDeepTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\flatMapDeep;
+
+class FlatMapDeepTest extends TestCase
+{
+    public function testFlatMapDeep()
+    {
+        $duplicate = function ($n) {
+            return [[[$n, $n]]];
+        };
+
+        $this->assertSame([1, 1, 2, 2], flatMapDeep([1, 2], $duplicate));
+    }
+}
diff --git a/tests/Collection/FlatMapDepthTest.php b/tests/Collection/FlatMapDepthTest.php
new file mode 100644
index 0000000..0cfea01
--- /dev/null
+++ b/tests/Collection/FlatMapDepthTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\flatMapDepth;
+use PHPUnit\Framework\TestCase;
+
+class FlatMapDepthTest extends TestCase
+{
+    public function testFlatMapDepth()
+    {
+        $duplicate = function ($n) {
+            return [[[$n, $n]]];
+        };
+
+        $this->assertSame([[1, 1], [2, 2]], flatMapDepth([1, 2], $duplicate, 2));
+    }
+}
diff --git a/tests/Collection/FlatMapTest.php b/tests/Collection/FlatMapTest.php
new file mode 100644
index 0000000..17bbcd6
--- /dev/null
+++ b/tests/Collection/FlatMapTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\flatMap;
+
+class FlatMapTest extends TestCase
+{
+    public function testFlatMap()
+    {
+        $duplicate = function ($n) {
+            return [$n, $n];
+        };
+
+        $this->assertSame([1, 1, 2, 2], flatMap([1, 2], $duplicate));
+    }
+}
diff --git a/tests/Collection/GroupByTest.php b/tests/Collection/GroupByTest.php
new file mode 100644
index 0000000..78cf4e7
--- /dev/null
+++ b/tests/Collection/GroupByTest.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\groupBy;
+
+class GroupByTest extends TestCase
+{
+    public function testCountBy()
+    {
+        $this->assertSame(['6' => [6.1, 6.3], '4' => [4.2]], groupBy([6.1, 4.2, 6.3], 'floor'));
+        $this->assertSame(['3' => ['one', 'two'], '5' => ['three']], groupBy(['one', 'two', 'three'], 'strlen'));
+    }
+}
diff --git a/tests/Collection/InvokeMapTest.php b/tests/Collection/InvokeMapTest.php
new file mode 100644
index 0000000..d1e4e11
--- /dev/null
+++ b/tests/Collection/InvokeMapTest.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\invokeMap;
+use PHPUnit\Framework\TestCase;
+
+class InvokeMapTest extends TestCase
+{
+    public function testInvokeMap()
+    {
+        $this->assertSame([[1, 5, 7], [1, 2, 3]], invokeMap([[5, 1, 7], [3, 2, 1]], function ($result) {
+            sort($result);
+            return $result;
+        }));
+        $this->assertSame([['1', '2', '3'], ['4', '5', '6']], invokeMap([123, 456], 'str_split'));
+
+        $users = [
+            new class() {
+                public function getCount()
+                {
+                    return 12;
+                }
+            },
+            new class() {
+                public function getCount()
+                {
+                    return 24;
+                }
+            }
+        ];
+
+        $this->assertEquals([12, 24], invokeMap($users, 'getCount'));
+    }
+}
diff --git a/tests/Collection/KeyByTest.php b/tests/Collection/KeyByTest.php
new file mode 100644
index 0000000..3ca8fc8
--- /dev/null
+++ b/tests/Collection/KeyByTest.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\keyBy;
+
+class KeyByTest extends TestCase
+{
+    public function testKeyBy()
+    {
+        $array = [
+            ['direction' => 'left', 'code' => 97],
+            ['direction' => 'right', 'code' => 100],
+        ];
+
+        $this->assertSame(['a' => ['direction' => 'left', 'code' => 97], 'd' => ['direction' => 'right', 'code' => 100]], keyBy($array, function ($o) {
+            return \chr($o['code']);
+        }));
+        $this->assertSame(['left' => ['direction' => 'left', 'code' => 97], 'right' => ['direction' => 'right', 'code' => 100]], keyBy($array, 'direction'));
+    }
+}
diff --git a/tests/Collection/MapTest.php b/tests/Collection/MapTest.php
index 0ac9fc9..c17a7ac 100644
--- a/tests/Collection/MapTest.php
+++ b/tests/Collection/MapTest.php
@@ -31,4 +31,4 @@ public function testChunk()
         $this->assertSame(['barney', 'fred'], map($users, 'user'));
         $this->assertSame(['barney', 'fred'], map(new \ArrayIterator($users), 'user'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Collection/OrderByTest.php b/tests/Collection/OrderByTest.php
new file mode 100644
index 0000000..1164c0d
--- /dev/null
+++ b/tests/Collection/OrderByTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\orderBy;
+
+class OrderByTest extends TestCase
+{
+    public function testOrderBy()
+    {
+        $users = [
+            ['user' => 'fred', 'age' => 48],
+            ['user' => 'barney', 'age' => 34],
+            ['user' => 'fred', 'age' => 40],
+            ['user' => 'barney', 'age' => 36],
+        ];
+
+        $this->assertSame([['user' => 'barney', 'age' => 36], ['user' => 'barney', 'age' => 34], ['user' => 'fred', 'age' => 48], ['user' => 'fred', 'age' => 40]], orderBy($users, ['user', 'age'], ['asc', 'desc']));
+    }
+}
diff --git a/tests/Collection/PartitionTest.php b/tests/Collection/PartitionTest.php
new file mode 100644
index 0000000..7c228ee
--- /dev/null
+++ b/tests/Collection/PartitionTest.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\partition;
+
+class PartitionTest extends TestCase
+{
+    public function testPartition()
+    {
+        $users = [
+            ['user' => 'barney', 'age' => 36, 'active' => false],
+            ['user' => 'fred', 'age' => 40, 'active' => true],
+            ['user' => 'pebbles', 'age' => 1, 'active' => false],
+        ];
+
+        $result = [
+            [
+                ['user' => 'fred', 'age' => 40, 'active' => true],
+            ],
+            [
+                ['user' => 'barney', 'age' => 36, 'active' => false],
+                ['user' => 'pebbles', 'age' => 1, 'active' => false],
+            ],
+        ];
+
+        $this->assertSame($result, partition($users, function ($user) {
+            return $user['active'];
+        }));
+    }
+}
diff --git a/tests/Collection/ReduceRightTest.php b/tests/Collection/ReduceRightTest.php
new file mode 100644
index 0000000..905fafd
--- /dev/null
+++ b/tests/Collection/ReduceRightTest.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\reduceRight;
+
+class ReduceRightTest extends TestCase
+{
+    public function testReduceRight()
+    {
+        $array = [[0, 1], [2, 3], [4, 5]];
+        $this->assertSame([4, 5, 2, 3, 0, 1], reduceRight($array, function ($flattened, $other) {
+            return \array_merge($flattened, $other);
+        }, []));
+    }
+}
diff --git a/tests/Collection/ReduceTest.php b/tests/Collection/ReduceTest.php
new file mode 100644
index 0000000..75e38e9
--- /dev/null
+++ b/tests/Collection/ReduceTest.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\reduce;
+
+class ReduceTest extends TestCase
+{
+    public function testReduce()
+    {
+        $this->assertSame(3, reduce([1, 2], function ($sum, $n) {
+            return $sum + $n;
+        }, 0));
+        $this->assertSame(['1' => ['a', 'c'], '2' => ['b']], reduce(['a' => 1, 'b' => 2, 'c' => 1], function ($result, $value, $key) {
+            if (!isset($result[$value])) {
+                $result[$value] = [];
+            }
+            $result[$value][] = $key;
+
+            return $result;
+        }, []));
+    }
+}
diff --git a/tests/Collection/RejectTest.php b/tests/Collection/RejectTest.php
new file mode 100644
index 0000000..bbfe2e2
--- /dev/null
+++ b/tests/Collection/RejectTest.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\reject;
+
+class RejectTest extends TestCase
+{
+    public function testReject()
+    {
+        $users = [
+            ['user' => 'barney', 'active' => true],
+            ['user' => 'fred', 'active' => false],
+        ];
+
+        $this->assertSame([['user' => 'fred', 'active' => false]], reject($users, 'active'));
+    }
+}
diff --git a/tests/Collection/SampleSizeTest.php b/tests/Collection/SampleSizeTest.php
new file mode 100644
index 0000000..b00bc98
--- /dev/null
+++ b/tests/Collection/SampleSizeTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\sampleSize;
+
+class SampleSizeTest extends TestCase
+{
+    public function testSampleSize()
+    {
+        $this->assertCount(2, sampleSize([1, 2, 3], 2));
+        $this->assertSame([], \array_diff(sampleSize([1, 2, 3], 2), [1, 2, 3]));
+
+        $this->assertCount(3, sampleSize([1, 2, 3], 4));
+        $this->assertSame([1, 2, 3], sampleSize([1, 2, 3], 4));
+    }
+}
diff --git a/tests/Collection/SampleTest.php b/tests/Collection/SampleTest.php
new file mode 100644
index 0000000..3730214
--- /dev/null
+++ b/tests/Collection/SampleTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\sample;
+use PHPUnit\Framework\TestCase;
+
+class SampleTest extends TestCase
+{
+    public function testSample()
+    {
+        $this->assertContains(sample([1, 2, 3, 4]), [1, 2, 3, 4]);
+    }
+}
diff --git a/tests/Collection/ShuffleTest.php b/tests/Collection/ShuffleTest.php
new file mode 100644
index 0000000..76e48c7
--- /dev/null
+++ b/tests/Collection/ShuffleTest.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\shuffle;
+use PHPUnit\Framework\TestCase;
+
+class ShuffleTest extends TestCase
+{
+    public function testShuffle()
+    {
+        $arr = range(1, 10);
+        $this->assertNotSame($arr, shuffle($arr));
+        $this->assertSame([], \array_diff($arr, shuffle($arr)));
+    }
+}
diff --git a/tests/Collection/SizeTest.php b/tests/Collection/SizeTest.php
new file mode 100644
index 0000000..b750e29
--- /dev/null
+++ b/tests/Collection/SizeTest.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\size;
+
+class SizeTest extends TestCase
+{
+    public function testSize()
+    {
+        $this->assertSame(3, size([1, 2, 3]));
+        $this->assertSame(2, size(new class {
+            public $a = 1;
+
+            public $b = 2;
+
+            private $c = 3;
+        }));
+
+        $this->assertSame(12, size(new class implements \Countable {
+            #[\ReturnTypeWillChange]
+            public function count()
+            {
+                return 12;
+            }
+        }));
+
+        $this->assertSame(4, size(new \ArrayIterator([1, 2, 3, 4])));
+
+        $this->assertSame(7, size('pebbles'));
+    }
+}
diff --git a/tests/Collection/SomeTest.php b/tests/Collection/SomeTest.php
new file mode 100644
index 0000000..b8c0b99
--- /dev/null
+++ b/tests/Collection/SomeTest.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\some;
+
+class SomeTest extends TestCase
+{
+    public function testSome()
+    {
+        $users = [
+            ['user' => 'barney', 'active' => true],
+            ['user' => 'fred', 'active' => false],
+        ];
+
+        $this->assertTrue(some([null, 0, 'yes', false], function ($value) {
+            return \is_bool($value);
+        }));
+        $this->assertFalse(some($users, ['user' => 'barney', 'active' => false]));
+        $this->assertTrue(some($users, ['active', false]));
+        $this->assertTrue(some($users, 'active'));
+    }
+}
diff --git a/tests/Collection/SortByTest.php b/tests/Collection/SortByTest.php
index f926edf..f1bb3c8 100644
--- a/tests/Collection/SortByTest.php
+++ b/tests/Collection/SortByTest.php
@@ -23,8 +23,10 @@ public function testSortBy()
             ['user' => 'barney', 'age' => 34],
         ];
 
-        $this->assertSame([['user' => 'barney', 'age' => 36], ['user' => 'barney', 'age' => 34], ['user' => 'fred', 'age' => 48], ['user' => 'fred', 'age' => 40]], sortBy($users, function ($o) { return $o['user']; }));
+        $this->assertSame([['user' => 'barney', 'age' => 36], ['user' => 'barney', 'age' => 34], ['user' => 'fred', 'age' => 48], ['user' => 'fred', 'age' => 40]], sortBy($users, function ($o) {
+            return $o['user'];
+        }));
         $this->assertSame([['user' => 'barney', 'age' => 34], ['user' => 'barney', 'age' => 36], ['user' => 'fred', 'age' => 40], ['user' => 'fred', 'age' => 48]], sortBy($users, ['user', 'age']));
         $this->assertSame([], sortBy(null, []));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Date/NowTest.php b/tests/Date/NowTest.php
index 578d1ec..3307998 100644
--- a/tests/Date/NowTest.php
+++ b/tests/Date/NowTest.php
@@ -19,4 +19,4 @@ public function testWords()
         // @TODO: This test is very volatile. Get a better way of testing a timestamp
         $this->assertSame((int) (\microtime(true) * 1000), now());
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Function/AfterTest.php b/tests/Function/AfterTest.php
new file mode 100644
index 0000000..ed0c6bc
--- /dev/null
+++ b/tests/Function/AfterTest.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\after;
+use PHPUnit\Framework\TestCase;
+
+class AfterTest extends TestCase
+{
+    public function testAfter()
+    {
+        $counter = 0;
+
+        $after = after(12, function () use (&$counter) {
+            $counter++;
+
+            return $counter;
+        });
+
+        for ($i = 0; $i < 12; $i++) {
+            $after();
+        }
+
+        $this->assertSame(1, $counter);
+    }
+
+    public function testAfterNotCalled()
+    {
+        $counter = 0;
+
+        $after = after(12, function () use (&$counter) {
+            $counter++;
+
+            return $counter;
+        });
+
+        for ($i = 0; $i < 10; $i++) {
+            $after();
+        }
+
+        $this->assertSame(0, $counter);
+    }
+}
diff --git a/tests/Function/AryTest.php b/tests/Function/AryTest.php
new file mode 100644
index 0000000..ef9ca60
--- /dev/null
+++ b/tests/Function/AryTest.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\ary;
+use function _\map;
+use PHPUnit\Framework\TestCase;
+
+class AryTest extends TestCase
+{
+    public function testAry()
+    {
+        $this->assertSame([6, 8, 10], map(['6', '8', '10'], ary('intval', 1)));
+    }
+}
diff --git a/tests/Function/BeforeTest.php b/tests/Function/BeforeTest.php
new file mode 100644
index 0000000..f43a968
--- /dev/null
+++ b/tests/Function/BeforeTest.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\before;
+use function _\map;
+use function _\uniqBy;
+use PHPUnit\Framework\TestCase;
+
+class BeforeTest extends TestCase
+{
+    public function testBefore()
+    {
+        $counter = 0;
+        $func = before(5, function () use (&$counter) {
+            $counter++;
+
+            return $counter;
+        });
+
+        for ($i = 0; $i < 20; $i++) {
+            $func();
+        }
+
+        $this->assertSame(4, $counter);
+        $this->assertSame(4, $func());
+    }
+
+    public function testBeforeMap()
+    {
+        $users = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+        $result = uniqBy(map($users, before(5, function (int $id) {
+            return [
+                'id' => $id
+            ];
+        })), 'id');
+
+        $this->assertSame([['id' => 1],['id' => 2],['id' => 3],['id' => 4]], $result);
+    }
+}
diff --git a/tests/Function/BindKeyTest.php b/tests/Function/BindKeyTest.php
new file mode 100644
index 0000000..7cfcc50
--- /dev/null
+++ b/tests/Function/BindKeyTest.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\bindKey;
+
+class BindKeyTest extends TestCase
+{
+    public function testBindKey()
+    {
+        $object = new class {
+            private $user = 'fred';
+
+            public function greet($greeting, $punctuation)
+            {
+                return $greeting.' '.$this->user.$punctuation;
+            }
+        };
+
+        $bound = bindKey($object, 'greet', 'hi');
+
+        $this->assertSame('hi fred!', $bound('!'));
+    }
+}
diff --git a/tests/Function/BindTest.php b/tests/Function/BindTest.php
new file mode 100644
index 0000000..a99a4f9
--- /dev/null
+++ b/tests/Function/BindTest.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\bind;
+
+class BindTest extends TestCase
+{
+    public function testBind()
+    {
+        $object = new class {
+            public $user = 'fred';
+
+            private $age = 54;
+        };
+
+        $greet = function ($greeting, $punctuation) {
+            return $greeting.' '.$this->user.$punctuation;
+        };
+
+        $bound = bind($greet, $object, 'hi');
+
+        $this->assertSame('hi fred!', $bound('!'));
+
+        $bound = bind(function ($prefix, $suffix) {
+            return $prefix.' '.$this->age.' '.$suffix;
+        }, $object, 'I\'m');
+
+        $this->assertSame('I\'m 54 years', $bound('years'));
+    }
+}
diff --git a/tests/Function/CurryTest.php b/tests/Function/CurryTest.php
new file mode 100644
index 0000000..a267362
--- /dev/null
+++ b/tests/Function/CurryTest.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\curry;
+
+class CurryTest extends TestCase
+{
+    public function testCurry()
+    {
+        $abc = function ($a, $b, $c = null) {
+            return [$a, $b, $c];
+        };
+
+        $curried = curry($abc);
+
+        $this->assertSame([1, 2, 3], $curried(1)(2)(3));
+        $this->assertSame([1, 2, 3], $curried(1, 2)(3));
+        $this->assertSame([1, 2, 3], $curried(1, 2, 3));
+        $this->assertSame([1, 2, null], curry($abc, 2)(1)(2));
+        $this->assertSame([1, 2, 3], $curried(1)(_, 3)(2));
+    }
+}
diff --git a/tests/Function/DelayTest.php b/tests/Function/DelayTest.php
new file mode 100644
index 0000000..65e1465
--- /dev/null
+++ b/tests/Function/DelayTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\delay;
+use PHPUnit\Framework\TestCase;
+
+class DelayTest extends TestCase
+{
+    public function testDelay()
+    {
+        $a = 1;
+        $time = microtime(true);
+        delay(function ($increment) use (&$a) {
+            $a += $increment;
+        }, 20, 2);
+
+        $this->assertSame(3, $a);
+        $this->assertTrue(((microtime(true) - $time) * 1000) > 20);
+    }
+}
diff --git a/tests/Function/FlipTest.php b/tests/Function/FlipTest.php
new file mode 100644
index 0000000..2e7ef83
--- /dev/null
+++ b/tests/Function/FlipTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\flip;
+
+class FlipTest extends TestCase
+{
+    public function testFlip()
+    {
+        $flipped = flip(function () {
+            return func_get_args();
+        });
+
+        $this->assertSame(['d', 'c', 'b', 'a'], $flipped('a', 'b', 'c', 'd'));
+    }
+}
diff --git a/tests/Function/MemoizeTest.php b/tests/Function/MemoizeTest.php
new file mode 100644
index 0000000..26a8938
--- /dev/null
+++ b/tests/Function/MemoizeTest.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\memoize;
+
+class MemoizeTest extends TestCase
+{
+    public function testMemoize()
+    {
+        $object = (object) ['a' => 1, 'b' => 2];
+        $other = (object) ['c' => 3, 'd' => 4];
+
+        $values = memoize('get_object_vars');
+        $this->assertSame(['a' => 1, 'b' => 2], $values($object));
+        $this->assertSame(['c' => 3, 'd' => 4], $values($other));
+
+        $object->a = 2;
+
+        $this->assertSame(['a' => 1, 'b' => 2], $values($object));
+
+        // Modify the result cache.
+        $values->cache->set($object, ['a', 'b']);
+        $this->assertSame(['a', 'b'], $values($object));
+    }
+}
diff --git a/tests/Function/NegateTest.php b/tests/Function/NegateTest.php
new file mode 100644
index 0000000..2e03b0f
--- /dev/null
+++ b/tests/Function/NegateTest.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\filter;
+use function _\negate;
+
+class NegateTest extends TestCase
+{
+    public function testNegate()
+    {
+        $isEven = function ($n) {
+            return $n % 2 == 0;
+        };
+
+        $this->assertSame([1, 3, 5], filter([1, 2, 3, 4, 5, 6], negate($isEven)));
+    }
+}
diff --git a/tests/Function/OnceTest.php b/tests/Function/OnceTest.php
new file mode 100644
index 0000000..96e057e
--- /dev/null
+++ b/tests/Function/OnceTest.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\once;
+
+class OnceTest extends TestCase
+{
+    public function testOnce()
+    {
+        $counter = 0;
+
+        $func = once(function () use (&$counter) {
+            $counter++;
+        });
+
+        $func();
+        $func();
+
+        $this->assertSame(1, $counter);
+    }
+}
diff --git a/tests/Function/OverArgsTest.php b/tests/Function/OverArgsTest.php
new file mode 100644
index 0000000..197fea6
--- /dev/null
+++ b/tests/Function/OverArgsTest.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\overArgs;
+
+class OverArgsTest extends TestCase
+{
+    public function testOverArgs()
+    {
+        function doubled($n)
+        {
+            return $n * 2;
+        }
+
+        function square($n)
+        {
+            return $n * $n;
+        }
+
+        $func = overArgs(function ($x, $y) {
+            return [$x, $y];
+        }, ['square', 'doubled']);
+
+        $this->assertSame([81, 6], $func(9, 3));
+
+        $this->assertSame([100, 10], $func(10, 5));
+    }
+}
diff --git a/tests/Function/PartialTest.php b/tests/Function/PartialTest.php
new file mode 100644
index 0000000..2a2c8c1
--- /dev/null
+++ b/tests/Function/PartialTest.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\partial;
+
+class PartialTest extends TestCase
+{
+    public function testPartial()
+    {
+        $greet = function ($greeting, $name) {
+            return $greeting.' '.$name;
+        };
+
+        $sayHelloTo = partial($greet, 'hello');
+        $this->assertSame('hello fred', $sayHelloTo('fred'));
+    }
+}
diff --git a/tests/Function/RestTest.php b/tests/Function/RestTest.php
new file mode 100644
index 0000000..58ad8d0
--- /dev/null
+++ b/tests/Function/RestTest.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\initial;
+use function _\last;
+use function _\rest;
+use function _\size;
+
+class RestTest extends TestCase
+{
+    public function testRest()
+    {
+        $say = rest(function ($what, $names) {
+            return $what.' '.implode(', ', initial($names)).
+                (size($names) > 1 ? ', & ' : '').last($names);
+        });
+
+        $this->assertSame('hello fred, barney, & pebbles', $say('hello', 'fred', 'barney', 'pebbles'));
+    }
+}
diff --git a/tests/Function/SpreadTest.php b/tests/Function/SpreadTest.php
new file mode 100644
index 0000000..b7b6cdb
--- /dev/null
+++ b/tests/Function/SpreadTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\spread;
+
+class SpreadTest extends TestCase
+{
+    public function testSpread()
+    {
+        $say = spread(function ($who, $what) {
+            return $who.' says '.$what;
+        });
+
+        $this->assertSame('fred says hello', $say(['fred', 'hello']));
+    }
+}
diff --git a/tests/Function/UnaryTest.php b/tests/Function/UnaryTest.php
new file mode 100644
index 0000000..b68c439
--- /dev/null
+++ b/tests/Function/UnaryTest.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\map;
+use function _\unary;
+use PHPUnit\Framework\TestCase;
+
+class UnaryTest extends TestCase
+{
+    public function testUnary()
+    {
+        $this->assertSame([6, 8, 10], map(['6', '8', '10'], unary('intval')));
+    }
+}
diff --git a/tests/Function/WrapTest.php b/tests/Function/WrapTest.php
new file mode 100644
index 0000000..008485f
--- /dev/null
+++ b/tests/Function/WrapTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\wrap;
+use PHPUnit\Framework\TestCase;
+
+class WrapTest extends TestCase
+{
+    public function testWrap()
+    {
+        $p = wrap('_\escape', function ($func, $text) {
+            return '<p>' . $func($text) . '</p>';
+        });
+
+        $this->assertSame('<p>fred, barney, &amp; pebbles</p>', $p('fred, barney, & pebbles'));
+    }
+}
diff --git a/tests/Lang/EqTest.php b/tests/Lang/EqTest.php
new file mode 100644
index 0000000..01083d6
--- /dev/null
+++ b/tests/Lang/EqTest.php
@@ -0,0 +1,93 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\eq;
+
+class EqTest extends TestCase
+{
+    /**
+     * @dataProvider equalValues
+     */
+    public function testIsEqual($value, $other)
+    {
+        $this->assertTrue(eq($value, $other));
+    }
+
+    /**
+     * @dataProvider notEqualValues
+     */
+    public function testIsNotEqual($value, $other)
+    {
+        $this->assertFalse(eq($value, $other));
+    }
+
+    public function notEqualValues()
+    {
+        $ob1 = new StdClass();
+        $ob1->a = 'b';
+        $ob2 = new StdClass();
+
+        $ob3 = new StdClass();
+        $ob4 = new StdClass();
+
+        return [
+            [
+                null, 'a',
+            ],
+            [
+                0, 1,
+            ],
+            [
+                [1], [],
+            ],
+            [
+                ['a' => 21], ['a' => 22],
+            ],
+            [
+                ['a' => 21], ['a' => '21'],
+            ],
+            [
+                $ob1, $ob2,
+            ],
+
+            [
+                $ob3, $ob4,
+            ],
+            [
+                new DateTime('NOW'), new DateTime('NOW'),
+            ],
+        ];
+    }
+
+    public function equalValues()
+    {
+        $date = new DateTime('NOW');
+
+        return [
+            [
+                'a', 'a',
+            ],
+            [
+                1, 1,
+            ],
+            [
+                [], [],
+            ],
+            [
+                $date, $date,
+            ],
+            [
+                INF, INF
+            ]
+        ];
+    }
+}
diff --git a/tests/Lang/IsEqualTest.php b/tests/Lang/IsEqualTest.php
index 8ce630c..f054cfa 100644
--- a/tests/Lang/IsEqualTest.php
+++ b/tests/Lang/IsEqualTest.php
@@ -86,4 +86,4 @@ public function equalValues()
             ],
         ];
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Lang/IsErrorTest.php b/tests/Lang/IsErrorTest.php
index be2af2a..4d09881 100644
--- a/tests/Lang/IsErrorTest.php
+++ b/tests/Lang/IsErrorTest.php
@@ -35,4 +35,4 @@ public function testIsError()
         $this->assertFalse(isError(new \stdClass()));
         $this->assertFalse(isError(\Exception::class));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/LodashTest.php b/tests/LodashTest.php
new file mode 100644
index 0000000..fae6947
--- /dev/null
+++ b/tests/LodashTest.php
@@ -0,0 +1,25 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+
+class LodashTest extends TestCase
+{
+    public function testChain()
+    {
+        $users = [
+            ['user' => 'barney', 'age' => 36],
+            ['user' => 'fred', 'age' => 40],
+            ['user' => 'pebbles', 'age' => 1],
+        ];
+
+        $youngest = __($users)
+            ->sortBy('age')
+            ->map(function ($o) {
+                return $o['user'] . ' is ' . $o['age'];
+            })
+            ->head()
+            ->value();
+
+        $this->assertSame('pebbles is 1', $youngest);
+    }
+}
diff --git a/tests/Math/AddTest.php b/tests/Math/AddTest.php
new file mode 100644
index 0000000..3c3e130
--- /dev/null
+++ b/tests/Math/AddTest.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\add;
+
+class AddTest extends TestCase
+{
+    public function testAdd()
+    {
+        $this->assertSame(10, add(6, 4));
+    }
+}
diff --git a/tests/Math/MaxByTest.php b/tests/Math/MaxByTest.php
new file mode 100644
index 0000000..77deba1
--- /dev/null
+++ b/tests/Math/MaxByTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\maxBy;
+
+class MaxByTest extends TestCase
+{
+    public function testMax()
+    {
+        $objects = [['n' => 1], ['n' => 2]];
+        $this->assertSame(['n' => 2], maxBy($objects, function ($o) {
+            return $o['n'];
+        }));
+        $this->assertSame(['n' => 2], maxBy($objects, 'n'));
+    }
+}
diff --git a/tests/Math/MaxTest.php b/tests/Math/MaxTest.php
new file mode 100644
index 0000000..ed8ddb0
--- /dev/null
+++ b/tests/Math/MaxTest.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\max;
+
+class MaxTest extends TestCase
+{
+    public function testMax()
+    {
+        $this->assertSame(8, max([4, 2, 8, 6]));
+        $this->assertSame(null, max([]));
+    }
+}
diff --git a/tests/Number/ClampTest.php b/tests/Number/ClampTest.php
index 09e5a1a..a116c7b 100644
--- a/tests/Number/ClampTest.php
+++ b/tests/Number/ClampTest.php
@@ -19,4 +19,4 @@ public function testClamp()
         $this->assertSame(-5, clamp(-10, -5, 5));
         $this->assertSame(5, clamp(10, -5, 5));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Number/InRangeTest.php b/tests/Number/InRangeTest.php
index 3b73841..45fe4b3 100644
--- a/tests/Number/InRangeTest.php
+++ b/tests/Number/InRangeTest.php
@@ -28,4 +28,4 @@ public function testInRange()
         $this->assertTrue(inRange(-3, -2, -6));
         $this->assertTrue(inRange(4, 12));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Number/RandomTest.php b/tests/Number/RandomTest.php
index 8e5e443..6ad6d00 100644
--- a/tests/Number/RandomTest.php
+++ b/tests/Number/RandomTest.php
@@ -25,4 +25,4 @@ public function testRandom()
         $this->assertTrue(is_float(random(true)));
         $this->assertTrue(inRange(random(10, 5), 5, 11));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Object/GetTest.php b/tests/Object/GetTest.php
new file mode 100644
index 0000000..4fb02bb
--- /dev/null
+++ b/tests/Object/GetTest.php
@@ -0,0 +1,49 @@
+<?php
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2019
+ */
+
+use function _\get;
+use PHPUnit\Framework\TestCase;
+
+class GetTest extends TestCase
+{
+    public function testGetArray()
+    {
+        $actualValue1 = "data";
+        $sampleArray = ["key1" => ["key2" => ["key3" => $actualValue1, "key4" => ""]]];
+        $defaultValue = "default";
+        $this->assertSame($actualValue1, get($sampleArray, "key1.key2.key3", "default"), "Default To method 1 failed");
+        $this->assertSame($defaultValue, get($sampleArray, "key2.key2.key3", $defaultValue), "Default To method 2 failed");
+        $this->assertSame($actualValue1, get($sampleArray, ["key1","key2","key3"], $defaultValue), "Default To method 3 failed");
+        $this->assertSame($defaultValue, get($sampleArray, "key1.key2.key3.key4", $defaultValue), "Default To method 4 failed");
+        $this->assertSame($defaultValue, get($sampleArray, "key1.key2.key3.key4", $defaultValue), "Default To method 5 failed");
+        $this->assertSame($defaultValue, get($sampleArray, ["key1","key2","key3","key4"], $defaultValue), "Default To method 6 failed");
+        $this->assertSame("", get($sampleArray, "key1.key2.key4", $defaultValue), "Default To method 8 failed");
+
+        $this->assertSame($sampleArray["key1"]["key2"], _::get($sampleArray, "key1.key2", $defaultValue), "Default To method 9 failed");
+        $this->assertSame($defaultValue, _::get($sampleArray, "key1.key3", $defaultValue), "Default To method 10 failed");
+    }
+
+    public function testDefaultToObject()
+    {
+        $actualValue1 = "data";
+        $sampleArray = (object)["key1" => (object)["key2" => (object)["key3" => $actualValue1, "key4" => ""]]];
+        $defaultValue = "default";
+        $this->assertSame($actualValue1, get($sampleArray, "key1.key2.key3", $defaultValue), "Default To method object 1 failed");
+        $this->assertSame($defaultValue, get($sampleArray, "key2.key2.key3", $defaultValue), "Default To method object 2 failed");
+        $this->assertSame($actualValue1, get($sampleArray, ["key1","key2","key3"], $defaultValue), "Default To method object 3 failed");
+        $this->assertSame($defaultValue, get($sampleArray, "key1.key2.key3.key4", $defaultValue), "Default To method object 4 failed");
+        $this->assertSame($defaultValue, get($sampleArray, "key1.key2.key3.key4", $defaultValue), "Default To method object 5 failed");
+        $this->assertSame($defaultValue, get($sampleArray, ["key1","key2","key3","key4"], $defaultValue), "Default To method object 6 failed");
+        $this->assertSame("", get($sampleArray, "key1.key2.key4", $defaultValue), "Default To method object 8 failed");
+
+        $this->assertSame($sampleArray->key1->key2, _::get($sampleArray, "key1.key2", $defaultValue), "Default To method object 9 failed");
+        $this->assertSame($defaultValue, _::get($sampleArray, "key1.key3", $defaultValue), "Default To method 10 failed");
+    }
+}
diff --git a/tests/Object/PickByTest.php b/tests/Object/PickByTest.php
new file mode 100644
index 0000000..5683f57
--- /dev/null
+++ b/tests/Object/PickByTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\pickBy;
+
+class PickByTest extends TestCase
+{
+    public function testPick()
+    {
+        $object = (object) ['a' => 1, 'b' => '2', 'c' => 3];
+
+        $this->assertEquals((object) ['a' => 1, 'c' => 3], pickBy($object, function ($value) {
+            return \is_int($value);
+        }));
+    }
+}
diff --git a/tests/Object/PickTest.php b/tests/Object/PickTest.php
new file mode 100644
index 0000000..3b1f9f4
--- /dev/null
+++ b/tests/Object/PickTest.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\pick;
+
+class PickTest extends TestCase
+{
+    public function testPick()
+    {
+        $object = (object) ['a' => 1, 'b' => '2', 'c' => 3];
+        $this->assertEquals((object) ['a' => 1, 'c' => 3], pick($object, ['a', 'c']));
+
+        $this->assertEquals((object) ['a' => 1], pick($object, 'a'));
+    }
+}
diff --git a/tests/Seq/ChainTest.php b/tests/Seq/ChainTest.php
new file mode 100644
index 0000000..f647cff
--- /dev/null
+++ b/tests/Seq/ChainTest.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use function _\chain;
+use PHPUnit\Framework\TestCase;
+
+class ChainTest extends TestCase
+{
+    public function testChain()
+    {
+        $users = [
+            ['user' => 'barney', 'age' => 36],
+            ['user' => 'fred', 'age' => 40],
+            ['user' => 'pebbles', 'age' => 1],
+        ];
+
+        $youngest = chain($users)
+            ->sortBy('age')
+            ->map(function ($o) {
+                return $o['user'] . ' is ' . $o['age'];
+            })
+            ->head()
+            ->value();
+
+        $this->assertSame('pebbles is 1', $youngest);
+    }
+}
diff --git a/tests/String/CamelCaseTest.php b/tests/String/CamelCaseTest.php
index d387682..cedc95b 100644
--- a/tests/String/CamelCaseTest.php
+++ b/tests/String/CamelCaseTest.php
@@ -20,4 +20,4 @@ public function testWords()
         $this->assertSame('fooBar', camelCase('--foo-bar--'));
         $this->assertSame('fooBar', camelCase('__FOO_BAR__'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/CapitalizeTest.php b/tests/String/CapitalizeTest.php
index 36b3762..a2f9b14 100644
--- a/tests/String/CapitalizeTest.php
+++ b/tests/String/CapitalizeTest.php
@@ -18,4 +18,4 @@ public function testWords()
     {
         $this->assertSame('Fred', capitalize('FRED'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/DeburrTest.php b/tests/String/DeburrTest.php
index e269b0b..b5c2eac 100644
--- a/tests/String/DeburrTest.php
+++ b/tests/String/DeburrTest.php
@@ -18,4 +18,4 @@ public function testWords()
     {
         $this->assertSame('deja vu', deburr('déjà vu'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/EndsWithTest.php b/tests/String/EndsWithTest.php
index 4e2748f..158c4c5 100644
--- a/tests/String/EndsWithTest.php
+++ b/tests/String/EndsWithTest.php
@@ -22,4 +22,4 @@ public function testWords()
         $this->assertFalse(endsWith('abc', 'b'));
         $this->assertTrue(endsWith('abc', 'b', 2));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/EscapeRegExpTest.php b/tests/String/EscapeRegExpTest.php
index 7b37090..c26c866 100644
--- a/tests/String/EscapeRegExpTest.php
+++ b/tests/String/EscapeRegExpTest.php
@@ -18,4 +18,4 @@ public function testEscapeRegExp()
     {
         $this->assertSame('\[lodash\]\(https://lodash\.com/\)', escapeRegExp('[lodash](https://lodash.com/)'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/EscapeTest.php b/tests/String/EscapeTest.php
index d772754..fb5671b 100644
--- a/tests/String/EscapeTest.php
+++ b/tests/String/EscapeTest.php
@@ -18,4 +18,4 @@ public function testEscape()
     {
         $this->assertSame('fred, barney, &amp; pebbles', escape('fred, barney, & pebbles'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/KebabCaseTest.php b/tests/String/KebabCaseTest.php
index bfcad01..d1b50c5 100644
--- a/tests/String/KebabCaseTest.php
+++ b/tests/String/KebabCaseTest.php
@@ -20,4 +20,4 @@ public function testKebabCase()
         $this->assertSame('foo-bar', kebabCase('fooBar'));
         $this->assertSame('foo-bar', kebabCase('__FOO_BAR__'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/LowerCaseTest.php b/tests/String/LowerCaseTest.php
index 4d3d5ef..166654a 100644
--- a/tests/String/LowerCaseTest.php
+++ b/tests/String/LowerCaseTest.php
@@ -20,4 +20,4 @@ public function testLowerCase()
         $this->assertSame('foo bar', lowerCase('fooBar'));
         $this->assertSame('foo bar', lowerCase('__FOO_BAR__'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/LowerFirstTest.php b/tests/String/LowerFirstTest.php
index bb817ff..6dedbc0 100644
--- a/tests/String/LowerFirstTest.php
+++ b/tests/String/LowerFirstTest.php
@@ -19,4 +19,4 @@ public function testLowerFirst()
         $this->assertSame('fred', lowerFirst('Fred'));
         $this->assertSame('fRED', lowerFirst('FRED'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/PadEndTest.php b/tests/String/PadEndTest.php
index a31d30e..5ee4056 100644
--- a/tests/String/PadEndTest.php
+++ b/tests/String/PadEndTest.php
@@ -20,4 +20,4 @@ public function testPadEnd()
         $this->assertSame('abc_-_', padEnd('abc', 6, '_-'));
         $this->assertSame('abc', padEnd('abc', 2));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/PadStartTest.php b/tests/String/PadStartTest.php
index 3679329..c208936 100644
--- a/tests/String/PadStartTest.php
+++ b/tests/String/PadStartTest.php
@@ -20,4 +20,4 @@ public function testPadStart()
         $this->assertSame('_-_abc', padStart('abc', 6, '_-'));
         $this->assertSame('abc', padStart('abc', 2));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/PadTest.php b/tests/String/PadTest.php
index 62da82a..720c1a0 100644
--- a/tests/String/PadTest.php
+++ b/tests/String/PadTest.php
@@ -20,4 +20,4 @@ public function testPad()
         $this->assertSame('_-abc_-_', pad('abc', 8, '_-'));
         $this->assertSame('abc', pad('abc', 2));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/ParseIntTest.php b/tests/String/ParseIntTest.php
index d47f53b..9a0147e 100644
--- a/tests/String/ParseIntTest.php
+++ b/tests/String/ParseIntTest.php
@@ -19,4 +19,4 @@ public function testParseInt()
         $this->assertSame(8, parseInt('08'));
         $this->assertSame(8, parseInt('08', 10));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/RepeatTest.php b/tests/String/RepeatTest.php
index 316b013..e6f2aea 100644
--- a/tests/String/RepeatTest.php
+++ b/tests/String/RepeatTest.php
@@ -20,4 +20,4 @@ public function testRepeat()
         $this->assertSame('abcabc', repeat('abc', 2));
         $this->assertSame('', repeat('abc', 0));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/ReplaceTest.php b/tests/String/ReplaceTest.php
index 3a65730..e1bba2f 100644
--- a/tests/String/ReplaceTest.php
+++ b/tests/String/ReplaceTest.php
@@ -23,4 +23,4 @@ public function testReplace()
             return implode(' - ', [$p1, $p2, $p3]);
         }));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/SnakeCaseTest.php b/tests/String/SnakeCaseTest.php
index 307ff7e..bffefc0 100644
--- a/tests/String/SnakeCaseTest.php
+++ b/tests/String/SnakeCaseTest.php
@@ -20,4 +20,4 @@ public function testSnakeCase()
         $this->assertSame('foo_bar', snakeCase('fooBar'));
         $this->assertSame('foo_bar', snakeCase('--FOO-BAR--'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/SplitTest.php b/tests/String/SplitTest.php
index 7d42e39..56826c7 100644
--- a/tests/String/SplitTest.php
+++ b/tests/String/SplitTest.php
@@ -22,4 +22,4 @@ public function testSplit()
         $this->assertSame(['Hello', 'World.', 'How'], split('Hello World. How are you doing?', ' ', 3));
         $this->assertSame(['Hello ', '1', ' word. Sentence number ', '2', '.'], split('Hello 1 word. Sentence number 2.', '/(\d)/'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/StartCaseTest.php b/tests/String/StartCaseTest.php
index 199cdcc..7bd7a95 100644
--- a/tests/String/StartCaseTest.php
+++ b/tests/String/StartCaseTest.php
@@ -20,4 +20,4 @@ public function testStartCase()
         $this->assertSame('Foo Bar', startCase('fooBar'));
         $this->assertSame('FOO BAR', startCase('__FOO_BAR__'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/StartsWithTest.php b/tests/String/StartsWithTest.php
index 7cf0fd9..e4c15a3 100644
--- a/tests/String/StartsWithTest.php
+++ b/tests/String/StartsWithTest.php
@@ -22,4 +22,4 @@ public function testStartsWith()
         $this->assertFalse(startsWith('abc', 'b'));
         $this->assertTrue(startsWith('abc', 'b', 1));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/TemplateTest.php b/tests/String/TemplateTest.php
index 17a1a3b..a51403d 100644
--- a/tests/String/TemplateTest.php
+++ b/tests/String/TemplateTest.php
@@ -42,4 +42,4 @@ public function testTemplate()
         $compiled = template('hello {{ user }}!');
         $this->assertSame('hello mustache!', $compiled(['user' => 'mustache']));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/ToLowerTest.php b/tests/String/ToLowerTest.php
index 7feffd3..74c6e4a 100644
--- a/tests/String/ToLowerTest.php
+++ b/tests/String/ToLowerTest.php
@@ -20,4 +20,4 @@ public function testToLower()
         $this->assertSame('foobar', toLower('fooBar'));
         $this->assertSame('__foo_bar__', toLower('__FOO_BAR__'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/ToUpperTest.php b/tests/String/ToUpperTest.php
index 5522ca7..a8eab10 100644
--- a/tests/String/ToUpperTest.php
+++ b/tests/String/ToUpperTest.php
@@ -20,4 +20,4 @@ public function testToUpper()
         $this->assertSame('FOOBAR', toUpper('fooBar'));
         $this->assertSame('__FOO_BAR__', toUpper('__foo_bar__'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/TrimEndTest.php b/tests/String/TrimEndTest.php
index 2c3d909..e387e7d 100644
--- a/tests/String/TrimEndTest.php
+++ b/tests/String/TrimEndTest.php
@@ -19,4 +19,4 @@ public function testTrimEnd()
         $this->assertSame('  abc', trimEnd('  abc  '));
         $this->assertSame('-_-abc', trimEnd('-_-abc-_-', '_-'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/TrimStartTest.php b/tests/String/TrimStartTest.php
index d962fd3..ad31ace 100644
--- a/tests/String/TrimStartTest.php
+++ b/tests/String/TrimStartTest.php
@@ -19,4 +19,4 @@ public function testTrimStart()
         $this->assertSame('abc  ', trimStart('  abc  '));
         $this->assertSame('abc-_-', trimStart('-_-abc-_-', '_-'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/TrimTest.php b/tests/String/TrimTest.php
index 026955c..ee5ce95 100644
--- a/tests/String/TrimTest.php
+++ b/tests/String/TrimTest.php
@@ -19,4 +19,4 @@ public function testTrim()
         $this->assertSame('abc', trim('  abc  '));
         $this->assertSame('abc', trim('-_-abc-_-', '_-'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/TruncateTest.php b/tests/String/TruncateTest.php
index bd6ed4d..c0837d1 100644
--- a/tests/String/TruncateTest.php
+++ b/tests/String/TruncateTest.php
@@ -25,4 +25,4 @@ public function testTruncate()
         $this->assertSame("hi-diddly-ho there,\u{e800}neighbo...", truncate("hi-diddly-ho there,\u{e800}neighborino"));
         $this->assertSame("hi-diddly-ho there, \u{e800} neigh...", truncate("hi-diddly-ho there, \u{e800} neighborino", ['separator' => '/\s?+/']));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/UnescapeTest.php b/tests/String/UnescapeTest.php
index 4dca468..1e41638 100644
--- a/tests/String/UnescapeTest.php
+++ b/tests/String/UnescapeTest.php
@@ -18,4 +18,4 @@ public function testUnescape()
     {
         $this->assertSame('fred, barney, & pebbles', unescape('fred, barney, &amp; pebbles'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/UpperCaseTest.php b/tests/String/UpperCaseTest.php
index 41f488c..af860d8 100644
--- a/tests/String/UpperCaseTest.php
+++ b/tests/String/UpperCaseTest.php
@@ -20,4 +20,4 @@ public function testUpperCase()
         $this->assertSame('FOO BAR', upperCase('fooBar'));
         $this->assertSame('FOO BAR', upperCase('__foo_bar__'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/UpperFirstTest.php b/tests/String/UpperFirstTest.php
index cd5cd43..ef2222b 100644
--- a/tests/String/UpperFirstTest.php
+++ b/tests/String/UpperFirstTest.php
@@ -19,4 +19,4 @@ public function testUpperFirst()
         $this->assertSame('Fred', upperFirst('fred'));
         $this->assertSame('FRED', upperFirst('FRED'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/String/WordsTest.php b/tests/String/WordsTest.php
index 603301c..7a3b28c 100644
--- a/tests/String/WordsTest.php
+++ b/tests/String/WordsTest.php
@@ -21,4 +21,4 @@ public function testWords()
         $this->assertSame([], words('fred, barney, & pebbles', '/[\d]+/'));
         $this->assertSame([], words("\u{e800}"));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Util/AttemptTest.php b/tests/Util/AttemptTest.php
index feaa167..b384e03 100644
--- a/tests/Util/AttemptTest.php
+++ b/tests/Util/AttemptTest.php
@@ -28,4 +28,4 @@ public function testAttempt()
             return 'one';
         })));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Util/DefaultToTest.php b/tests/Util/DefaultToTest.php
new file mode 100644
index 0000000..f428473
--- /dev/null
+++ b/tests/Util/DefaultToTest.php
@@ -0,0 +1,26 @@
+<?php
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2019
+ */
+
+use function _\defaultTo;
+use PHPUnit\Framework\TestCase;
+
+class DefaultToTest extends TestCase
+{
+    public function testDefaultTo()
+    {
+        $null = null;
+        $default = "defaultValue";
+        $realValue = "string";
+        $this->assertSame($default, defaultTo($null, $default), "DefaultTo 1 failed");
+        $this->assertSame($default, defaultTo(NAN, $default), "DefaultTo 2 failed");
+        $this->assertSame($realValue, defaultTo($realValue, $default), "DefaultTo 3 failed");
+        $this->assertSame("", defaultTo("", $default), "DefaultTo 4 failed");
+    }
+}
diff --git a/tests/Util/IdentityTest.php b/tests/Util/IdentityTest.php
index 4ee9406..a2c35bd 100644
--- a/tests/Util/IdentityTest.php
+++ b/tests/Util/IdentityTest.php
@@ -20,4 +20,4 @@ public function testIdentity()
 
         $this->assertSame($object, identity($object));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Util/PropertyTest.php b/tests/Util/PropertyTest.php
index d07eca5..e0d7afa 100644
--- a/tests/Util/PropertyTest.php
+++ b/tests/Util/PropertyTest.php
@@ -26,4 +26,4 @@ public function testIdentity()
         $this->assertSame([2, 1], map($objects, property('a.b')));
         $this->assertSame([1, 2], map(sortBy($objects, property(['a', 'b'])), 'a.b'));
     }
-}
\ No newline at end of file
+}

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