Add AndAll type (#1383)

Author: som-sm

index.d.ts

@@ -155,6 +155,7 @@ export type {IsNull} from './source/is-null.d.ts';
 export type {IfNull} from './source/if-null.d.ts';
 export type {IsUndefined} from './source/is-undefined.d.ts';
 export type {And} from './source/and.d.ts';
+export type {AndAll} from './source/and-all.d.ts';
 export type {Or} from './source/or.d.ts';
 export type {OrAll} from './source/or-all.d.ts';
 export type {Xor} from './source/xor.d.ts';

readme.md

@@ -183,6 +183,7 @@ Click the type names for complete docs.
 - [`And`](source/and.d.ts) - Returns a boolean for whether two given types are both `true`.
 - [`Or`](source/or.d.ts) - Returns a boolean for whether either of two given types is `true`.
 - [`Xor`](source/xor.d.ts) - Returns a boolean for whether only one of two given types is `true`.
+- [`AndAll`](source/and-all.d.ts) - Returns a boolean for whether all of the given elements are `true`.
 - [`OrAll`](source/or-all.d.ts) - Returns a boolean for whether any of the given elements is `true`.
 - [`AllExtend`](source/all-extend.d.ts) - Returns a boolean for whether every element in an array type extends another type.
 - [`SomeExtend`](source/some-extend.d.ts) - Returns a boolean for whether some element in an array type extends another type.

source/and-all.d.ts

@@ -0,0 +1,76 @@
+import type {AllExtend} from './all-extend.d.ts';
+
+/**
+Returns a boolean for whether all of the given elements are `true`.
+
+Use-cases:
+- Check if all conditions in a list of booleans are met.
+
+@example
+```
+import type {AndAll} from 'type-fest';
+
+type TTT = AndAll<[true, true, true]>;
+//=> true
+
+type TTF = AndAll<[true, true, false]>;
+//=> false
+
+type TFT = AndAll<[true, false, true]>;
+//=> false
+```
+
+Note: When `boolean` is passed as an element, it is distributed into separate cases, and the final result is a union of those cases.
+For example, `AndAll<[true, boolean]>` expands to `AndAll<[true, true]> | AndAll<[true, false]>`, which simplifies to `true | false` (i.e., `boolean`).
+
+@example
+```
+import type {AndAll} from 'type-fest';
+
+type A = AndAll<[true, boolean]>;
+//=> boolean
+
+type B = AndAll<[false, boolean]>;
+//=> false
+```
+
+Note: If any of the elements is `never`, the result becomes `false`.
+
+@example
+```
+import type {AndAll} from 'type-fest';
+
+type A = AndAll<[true, true, never]>;
+//=> false
+
+type B = AndAll<[false, never, never]>;
+//=> false
+
+type C = AndAll<[never, never, never]>;
+//=> false
+
+type D = AndAll<[boolean, true, never]>;
+//=> false
+```
+
+Note: If `any` is passed as an element, it is treated as `boolean` and the result is computed accordingly.
+
+@example
+```
+import type {AndAll} from 'type-fest';
+
+type A = AndAll<[false, any]>;
+//=> false
+
+type B = AndAll<[true, any]>;
+//=> boolean
+```
+
+Note: `AndAll<[]>` evaluates to `true` due to the concept of [vacuous truth](https://en.wikipedia.org/wiki/Logical_conjunction#:~:text=In%20keeping%20with%20the%20concept%20of%20vacuous%20truth%2C%20when%20conjunction%20is%20defined%20as%20an%20operator%20or%20function%20of%20arbitrary%20arity%2C%20the%20empty%20conjunction%20(AND%2Ding%20over%20an%20empty%20set%20of%20operands)%20is%20often%20defined%20as%20having%20the%20result%20true.), i.e., there are no `false` elements in an empty tuple.
+
+@see {@link And}
+@see {@link OrAll}
+*/
+export type AndAll<T extends readonly boolean[]> = AllExtend<T, true>;
+
+export {};

source/and.d.ts

@@ -1,4 +1,4 @@
-import type {AllExtend} from './all-extend.d.ts';
+import type {AndAll} from './and-all.d.ts';
 
 /**
 Returns a boolean for whether two given types are both true.
@@ -73,9 +73,10 @@ type G = And<never, never>;
 //=> false
 ```
 
+@see {@link AndAll}
 @see {@link Or}
 @see {@link Xor}
 */
-export type And<A extends boolean, B extends boolean> = AllExtend<[A, B], true>;
+export type And<A extends boolean, B extends boolean> = AndAll<[A, B]>;
 
 export {};

source/or-all.d.ts

@@ -66,6 +66,7 @@ type B = OrAll<[true, any]>;
 Note: `OrAll<[]>` evaluates to `false` because there are no `true` elements in an empty tuple. See [Wikipedia: Clause (logic) > Empty clauses](https://en.wikipedia.org/wiki/Clause_(logic)#Empty_clauses:~:text=The%20truth%20evaluation%20of%20an%20empty%20disjunctive%20clause%20is%20always%20false.).
 
 @see {@link Or}
+@see {@link AndAll}
 */
 export type OrAll<T extends readonly boolean[]> = SomeExtend<T, true>;
 

test-d/and-all.ts

@@ -0,0 +1,63 @@
+import {expectType} from 'tsd';
+import type {AndAll} from '../source/and-all.d.ts';
+
+declare const boolean: boolean;
+
+// Basic boolean combinations
+expectType<AndAll<[true, true]>>(true);
+expectType<AndAll<[true, false]>>(false);
+expectType<AndAll<[false, true]>>(false);
+expectType<AndAll<[false, false]>>(false);
+
+// Multiple elements in a tuple
+expectType<AndAll<[true, true, true, true]>>(true);
+expectType<AndAll<[true, true, true, false]>>(false);
+expectType<AndAll<[true, true, false, true]>>(false);
+
+// `boolean` element
+expectType<AndAll<[true, true, boolean]>>(boolean);
+expectType<AndAll<[true, boolean, false]>>(false);
+expectType<AndAll<[boolean, boolean, boolean]>>(boolean);
+
+// Unions
+expectType<AndAll<[true, true, true] | [true, true, false]>>(boolean); // `true` | `false`
+expectType<AndAll<[true, true] | [true]>>(true); // `true` | `true`
+expectType<AndAll<[false] | [true, false, true]>>(false); // `false` | `false`
+expectType<AndAll<[true, true] | [true, boolean]>>(boolean); // `true` | `boolean`
+expectType<AndAll<[false, true] | [true, true, boolean]>>(boolean); // `false` | `boolean`
+expectType<AndAll<[boolean, true, true] | [boolean]>>(boolean); // `boolean` | `boolean`
+
+// Tuples with rest element
+expectType<AndAll<[true, ...Array<true>]>>(true);
+expectType<AndAll<[...Array<true>, false]>>(false);
+expectType<AndAll<[true, ...Array<true>, boolean]>>(boolean);
+
+// Non-tuple arrays
+expectType<AndAll<Array<true>>>(true);
+expectType<AndAll<Array<false>>>(false);
+expectType<AndAll<boolean[]>>(boolean);
+
+// Readonly arrays
+expectType<AndAll<readonly [true, true, true]>>(true);
+expectType<AndAll<readonly [true, true, false]>>(false);
+expectType<AndAll<readonly [true, true, boolean]>>(boolean);
+expectType<AndAll<ReadonlyArray<true>>>(true);
+expectType<AndAll<ReadonlyArray<false>>>(false);
+expectType<AndAll<readonly boolean[]>>(boolean);
+
+// Boundary cases
+expectType<AndAll<[]>>(true);
+
+expectType<AndAll<[any, any, false]>>(false);
+expectType<AndAll<[any, any, true]>>(boolean);
+expectType<AndAll<[any, any, any]>>(boolean);
+
+expectType<AndAll<[false, never, never]>>(false);
+expectType<AndAll<[true, true, never]>>(false);
+expectType<AndAll<[never, never, never]>>(false);
+
+// Errors with non-boolean or optional elements
+// @ts-expect-error
+type Error1 = AndAll<[1, 0]>;
+// @ts-expect-error
+type Error2 = AndAll<[true, false?]>;