Merge pull request #239 from aelshinawy/main

Mathys-Gasnier · web-flow · commit df7dcbfc26fc · 2025-01-26T11:40:31.000+01:00
[Snippets] Added some helper types for Typescript
diff --git a/snippets/typescript/helper-types/at-least-one-key.md b/snippets/typescript/helper-types/at-least-one-key.md
@@ -0,0 +1,23 @@
+---
+title:  At Least One Key
+description: Ensures that at least one property of an object is required.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition
+---
+
+```ts
+type AtLeastOne<T> = {
+    [K in keyof T]: Pick<T, K> & Partial<Omit<T, K>>;
+}[keyof T];
+
+
+// Usage:
+type A = {
+    id?: string;
+    name?: string;
+    isActive?: boolean;
+};
+
+type AtLeastOneA = AtLeastOne<A>;
+// Requires at least one of 'id', 'name', or 'isActive' to be defined
+```
diff --git a/snippets/typescript/helper-types/deep-partial-type.md b/snippets/typescript/helper-types/deep-partial-type.md
@@ -0,0 +1,34 @@
+---
+title: Deep Partial Type
+description: Converts all properties of a type, including nested objects, into optional.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition,optional
+---
+
+```ts
+type DeepPartial<T> = {
+    [K in keyof T]?: T[K] extends object ? DeepPartial<T[K]> : T[K];
+};
+
+
+// Usage:
+type A = {
+    name: string;
+    details: {
+        age: number;
+        address: { city: string; zip: string };
+    };
+};
+
+type PartialA = DeepPartial<A>;
+/*
+Type PartialA:
+{
+  name?: string;
+  details?: {
+    age?: number;
+    address?: { city?: string; zip?: string };
+  };
+}
+*/
+```
diff --git a/snippets/typescript/helper-types/deep-readonly-type.md b/snippets/typescript/helper-types/deep-readonly-type.md
@@ -0,0 +1,34 @@
+---
+title: Deep Readonly Type
+description: Converts all properties of a type, including nested objects, into readonly.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition,readonly
+---
+
+```ts
+type DeepReadonly<T> = {
+    readonly [K in keyof T]: T[K] extends object ? DeepReadonly<T[K]> : T[K];
+};
+
+
+// Usage:
+type A = {
+    name: string;
+    details: {
+        age: number;
+        address: { city: string; zip: string };
+    };
+};
+
+type ReadonlyA = DeepReadonly<A>;
+/*
+Type ReadonlyA:
+{
+  readonly name: string;
+  readonly details: {
+    readonly age: number;
+    readonly address: { readonly city: string; readonly zip: string };
+  };
+}
+*/
+```
diff --git a/snippets/typescript/helper-types/deep-required-type.md b/snippets/typescript/helper-types/deep-required-type.md
@@ -0,0 +1,26 @@
+---
+title: Deep Required Type
+description: Converts all properties of a type, including nested objects, into required.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition,required
+---
+
+```ts
+type DeepRequired<T> = T extends object
+    ? { [K in keyof T]-?: DeepRequired<T[K]> }
+    : T;
+
+
+// Usage:
+type A = {
+    id?: string;
+    name?: string;
+    details?: {
+        age?: number;
+        address?: { city?: string; zip?: string };
+    };
+};
+
+type RequiredA = DeepRequired<A>;
+// Result: { id: string; name: string; details: { age: number; address: { city: string; zip: string }; }; }
+```
diff --git a/snippets/typescript/helper-types/keys-of-type.md b/snippets/typescript/helper-types/keys-of-type.md
@@ -0,0 +1,16 @@
+---
+title: Keys of Type
+description: Extracts keys from an object type that match a specified value type.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition
+---
+
+```ts
+type KeysOfType<T, U> = { [K in keyof T]: T[K] extends U ? K : never }[keyof T];
+
+
+// Usage:
+type A = { name: string; age: number; isActive: boolean, isDeleted: boolean };
+type StringKeys = KeysOfType<A, string>; // "name"
+type BooleanKeys = KeysOfType<A, boolean>; // "isActive" | "isDeleted"
+```
diff --git a/snippets/typescript/helper-types/keys-to-optional.md b/snippets/typescript/helper-types/keys-to-optional.md
@@ -0,0 +1,24 @@
+---
+title:  Keys to Optional
+description: Makes only the specified keys of an object type optional.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition,optional
+---
+
+```ts
+type OptionalKeys<T, K extends keyof T> = Omit<T, K> & Partial<Pick<T, K>>;
+
+
+// Usage:
+type A = {
+    id: string;
+    name: string;
+    age: number;
+};
+
+type WithOptionalName = OptionalKeys<A, "name">;
+// { id: string; age: number; name?: string }
+
+type WithOptionalNameAndAge = OptionalKeys<A, "name" | "age">;
+// Result: { id: string; name?: string; age?: number }
+```
diff --git a/snippets/typescript/helper-types/nullable-keys.md b/snippets/typescript/helper-types/nullable-keys.md
@@ -0,0 +1,22 @@
+---
+title: Nullable Keys
+description: Extracts keys from an object type that allow null or undefined values.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition,nullable
+---
+
+```ts
+type NullableKeys<T> = {
+    [K in keyof T]: null extends T[K] ? K : undefined extends T[K] ? K : never;
+}[keyof T];
+
+
+// Usage:
+type A = {
+    id: string;
+    name?: string;
+    description: string | null;
+};
+
+type Nullable = NullableKeys<A>; // "name" | "description"
+```
diff --git a/snippets/typescript/helper-types/omit-keys-of-type.md b/snippets/typescript/helper-types/omit-keys-of-type.md
@@ -0,0 +1,22 @@
+---
+title: Omit Keys of Type
+description: Removes keys of a specified type from an object type.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition,omit,keys
+---
+
+```ts
+type OmitKeysOfType<T, U> = {
+    [K in keyof T as T[K] extends U ? never : K]: T[K];
+};
+
+
+// Usage:
+type A = {
+    id: string;
+    isActive: boolean;
+    data: number[];
+};
+
+type WithoutBoolean = OmitKeysOfType<A, boolean>; // { id: string; data: number[] }
+```
diff --git a/snippets/typescript/helper-types/required-keys.md b/snippets/typescript/helper-types/required-keys.md
@@ -0,0 +1,22 @@
+---
+title: Required Keys
+description: Extracts required keys from an object.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition,required
+---
+
+```ts
+type RequiredKeys<T> = {
+    [K in keyof T]-?: {} extends Pick<T, K> ? never : K;
+}[keyof T];
+
+
+// Usage:
+type A = {
+    id: string;
+    name?: string;
+    isActive: boolean;
+};
+
+type ReqKeys = RequiredKeys<A>; // "id" | "isActive"
+```
diff --git a/snippets/typescript/helper-types/union-to-intersection.md b/snippets/typescript/helper-types/union-to-intersection.md
@@ -0,0 +1,21 @@
+---
+title: Union to Intersection
+description: Converts a union type into an intersection type.
+author: aelshinawy
+tags: typescript,helper-types,typedefinition,intersection,union
+---
+
+```ts
+type UnionToIntersection<U> = (U extends any ? (arg: U) => void : never) extends (arg: infer I) => void
+    ? I
+    : never;
+
+
+// Usage:
+type A = { id: string };
+type B = { name: string };
+type C = { age: number };
+
+type Intersected = UnionToIntersection<A | B | C>;
+// { id: string } & { name: string } & { age: number }
+```
