docs(README): refresh README with gulp4 usage

twada · twada · commit 6ac3e3b3de6d · 2020-05-14T14:09:09.000+09:00
diff --git a/README.md b/README.md
@@ -4,9 +4,9 @@
 
 [![unassert][unassert-banner]][unassert-url]
 
-[![NPM version][npm-image]][npm-url]
 [![Build Status][travis-image]][travis-url]
-[![Dependency Status][depstat-image]][depstat-url]
+[![NPM version][npm-image]][npm-url]
+[![Code Style][style-image]][style-url]
 [![License][license-image]][license-url]
 
 
@@ -24,51 +24,88 @@
 - [unassert-cli](https://github.com/unassert-js/unassert-cli): CLI for unassert
 
 
-## Usage
-
-First, install `gulp-unassert` as a devDependencies:
+## Install
 
 ```shell
 npm install --save-dev gulp-unassert
 ```
 
-Then, add it to your `gulpfile.js`:
+## Usage
+
+### gulp 3.x
 
 ```javascript
-var unassert = require('gulp-unassert');
+const unassert = require('gulp-unassert');
 
-gulp.task('build', function () {
-    gulp.src('./src/*.js')
-        .pipe(unassert())
-        .pipe(gulp.dest('./dist'));
+gulp.task('build', () => {
+  gulp.src('./src/*.js')
+    .pipe(unassert())
+    .pipe(gulp.dest('./dist'));
 });
 ```
 
+### gulp 4.x
+
+```javascript
+const { src, dest } = require('gulp');
+const unassert = require('gulp-unassert');
+
+function build() {
+  return src('./src/*.js')
+    .pipe(unassert())
+    .pipe(dest('./dist'));
+}
+exports.build = build;
+```
+
 
 ## Source maps
 
-gulp-unassert can be used with [gulp-sourcemaps](https://github.com/floridoo/gulp-sourcemaps) to generate source maps for the transformed javascript code. Note that you should `init` gulp-sourcemaps prior to running the gulp-unassert and `write` the source maps after. gulp-unassert works well with some gulp plugins that supports [gulp-sourcemaps](https://github.com/floridoo/gulp-sourcemaps).
+### gulp 3.x
+
+gulp-unassert can be used with [gulp-sourcemaps](https://github.com/gulp-sourcemaps/gulp-sourcemaps) to generate source maps for the transformed javascript code. Note that you should `init` gulp-sourcemaps prior to running the gulp-unassert and `write` the source maps after. gulp-unassert works well with some gulp plugins that supports [gulp-sourcemaps](https://github.com/gulp-sourcemaps/gulp-sourcemaps).
 
 ```javascript
-var unassert = require('gulp-unassert');
-var coffee = require('gulp-coffee');
-var concat = require('gulp-concat');
-var sourcemaps = require('gulp-sourcemaps');
-
-gulp.task('build', function () {
-    // compile, instrument then concatinate
-    gulp.src('./src/**/*.coffee')
-        .pipe(sourcemaps.init())
-        .pipe(coffee({bare: true}))
-        .pipe(unassert())
-        .pipe(concat('bundle.js'))
-        .pipe(sourcemaps.write())
-        .pipe(gulp.dest('./build'));
-    // will write the source maps inline in the code
+const unassert = require('gulp-unassert');
+const coffee = require('gulp-coffee');
+const concat = require('gulp-concat');
+const sourcemaps = require('gulp-sourcemaps');
+
+gulp.task('build', () => {
+  // compile, instrument then concatinate
+  gulp.src('./src/**/*.coffee')
+    .pipe(sourcemaps.init())
+    .pipe(coffee({bare: true}))
+    .pipe(unassert())
+    .pipe(concat('bundle.js'))
+    .pipe(sourcemaps.write())
+    .pipe(gulp.dest('./build'));
+  // will write the source maps inline in the code
 });
 ```
 
-For more information, see [gulp-sourcemaps](https://github.com/floridoo/gulp-sourcemaps).
+For more information, see [gulp-sourcemaps](https://github.com/gulp-sourcemaps/gulp-sourcemaps).
+
+
+### gulp 4.x
+
+In gulp 4, sourcemaps are built-in by default.
+
+```javascript
+const { src, dest } = require('gulp');
+const unassert = require('gulp-unassert');
+const coffee = require('gulp-coffee');
+const concat = require('gulp-concat');
+
+function build() {
+  return src('./src/*.coffee', { sourcemaps: true })
+    .pipe(coffee({ bare: true }))
+    .pipe(unassert())
+    .pipe(concat('bundle.js'))
+    .pipe(dest('./build'));
+}
+exports.build = build;
+```
 
 
 ## Changelog
@@ -104,8 +141,8 @@ Licensed under the [MIT](https://github.com/unassert-js/gulp-unassert/blob/maste
 [travis-url]: https://travis-ci.org/unassert-js/gulp-unassert
 [travis-image]: https://secure.travis-ci.org/unassert-js/gulp-unassert.svg?branch=master
 
-[depstat-url]: https://gemnasium.com/unassert-js/gulp-unassert
-[depstat-image]: https://gemnasium.com/unassert-js/gulp-unassert.svg
-
 [license-url]: https://github.com/unassert-js/gulp-unassert/blob/master/LICENSE-MIT
 [license-image]: https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat
+
+[style-url]: https://github.com/Flet/semistandard
+[style-image]: https://img.shields.io/badge/code%20style-semistandard-brightgreen.svg
