Add a type-guard overload of Array.every (#38200)

Co-authored-by: Nathan Shively-Sanders <[email protected]>

Author: dmitri-gb

src/lib/es5.d.ts

@@ -1109,6 +1109,15 @@ interface ReadonlyArray<T> {
      * @param fromIndex The array index at which to begin the search. If fromIndex is omitted, the search starts at the last index in the array.
      */
     lastIndexOf(searchElement: T, fromIndex?: number): number;
+    /**
+     * Determines whether all the members of an array satisfy the specified test.
+     * @param callbackfn A function that accepts up to three arguments. The every method calls
+     * the callbackfn function for each element in the array until the callbackfn returns a value
+     * which is coercible to the Boolean value false, or until the end of the array.
+     * @param thisArg An object to which the this keyword can refer in the callbackfn function.
+     * If thisArg is omitted, undefined is used as the this value.
+     */
+    every<S extends T>(callbackfn: (value: T, index: number, array: readonly T[]) => value is S, thisArg?: any): this is readonly S[];
     /**
      * Determines whether all the members of an array satisfy the specified test.
      * @param callbackfn A function that accepts up to three arguments. The every method calls
@@ -1279,6 +1288,15 @@ interface Array<T> {
      * @param fromIndex The array index at which to begin the search. If fromIndex is omitted, the search starts at the last index in the array.
      */
     lastIndexOf(searchElement: T, fromIndex?: number): number;
+    /**
+     * Determines whether all the members of an array satisfy the specified test.
+     * @param callbackfn A function that accepts up to three arguments. The every method calls
+     * the callbackfn function for each element in the array until the callbackfn returns a value
+     * which is coercible to the Boolean value false, or until the end of the array.
+     * @param thisArg An object to which the this keyword can refer in the callbackfn function.
+     * If thisArg is omitted, undefined is used as the this value.
+     */
+    every<S extends T>(callbackfn: (value: T, index: number, array: T[]) => value is S, thisArg?: any): this is S[];
     /**
      * Determines whether all the members of an array satisfy the specified test.
      * @param callbackfn A function that accepts up to three arguments. The every method calls

tests/baselines/reference/2dArrays.symbols

@@ -25,11 +25,11 @@ class Board {
 >allShipsSunk : Symbol(Board.allShipsSunk, Decl(2dArrays.ts, 9, 18))
 
         return this.ships.every(function (val) { return val.isSunk; });
->this.ships.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>this.ships.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >this.ships : Symbol(Board.ships, Decl(2dArrays.ts, 7, 13))
 >this : Symbol(Board, Decl(2dArrays.ts, 5, 1))
 >ships : Symbol(Board.ships, Decl(2dArrays.ts, 7, 13))
->every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >val : Symbol(val, Decl(2dArrays.ts, 12, 42))
 >val.isSunk : Symbol(Ship.isSunk, Decl(2dArrays.ts, 3, 12))
 >val : Symbol(val, Decl(2dArrays.ts, 12, 42))

tests/baselines/reference/2dArrays.types

@@ -24,11 +24,11 @@ class Board {
 
         return this.ships.every(function (val) { return val.isSunk; });
 >this.ships.every(function (val) { return val.isSunk; }) : boolean
->this.ships.every : (callbackfn: (value: Ship, index: number, array: Ship[]) => unknown, thisArg?: any) => boolean
+>this.ships.every : { <S extends Ship>(callbackfn: (value: Ship, index: number, array: Ship[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: Ship, index: number, array: Ship[]) => unknown, thisArg?: any): boolean; }
 >this.ships : Ship[]
 >this : this
 >ships : Ship[]
->every : (callbackfn: (value: Ship, index: number, array: Ship[]) => unknown, thisArg?: any) => boolean
+>every : { <S extends Ship>(callbackfn: (value: Ship, index: number, array: Ship[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: Ship, index: number, array: Ship[]) => unknown, thisArg?: any): boolean; }
 >function (val) { return val.isSunk; } : (val: Ship) => boolean
 >val : Ship
 >val.isSunk : boolean

tests/baselines/reference/arrayEvery.js

@@ -0,0 +1,16 @@
+//// [arrayEvery.ts]
+const foo: (number | string)[] = ['aaa'];
+
+const isString = (x: unknown): x is string => typeof x === 'string';
+
+if (foo.every(isString)) {
+  foo[0].slice(0);
+}
+
+
+//// [arrayEvery.js]
+var foo = ['aaa'];
+var isString = function (x) { return typeof x === 'string'; };
+if (foo.every(isString)) {
+    foo[0].slice(0);
+}

tests/baselines/reference/arrayEvery.symbols

@@ -0,0 +1,22 @@
+=== tests/cases/compiler/arrayEvery.ts ===
+const foo: (number | string)[] = ['aaa'];
+>foo : Symbol(foo, Decl(arrayEvery.ts, 0, 5))
+
+const isString = (x: unknown): x is string => typeof x === 'string';
+>isString : Symbol(isString, Decl(arrayEvery.ts, 2, 5))
+>x : Symbol(x, Decl(arrayEvery.ts, 2, 18))
+>x : Symbol(x, Decl(arrayEvery.ts, 2, 18))
+>x : Symbol(x, Decl(arrayEvery.ts, 2, 18))
+
+if (foo.every(isString)) {
+>foo.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>foo : Symbol(foo, Decl(arrayEvery.ts, 0, 5))
+>every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>isString : Symbol(isString, Decl(arrayEvery.ts, 2, 5))
+
+  foo[0].slice(0);
+>foo[0].slice : Symbol(String.slice, Decl(lib.es5.d.ts, --, --))
+>foo : Symbol(foo, Decl(arrayEvery.ts, 0, 5))
+>slice : Symbol(String.slice, Decl(lib.es5.d.ts, --, --))
+}
+

tests/baselines/reference/arrayEvery.types

@@ -0,0 +1,32 @@
+=== tests/cases/compiler/arrayEvery.ts ===
+const foo: (number | string)[] = ['aaa'];
+>foo : (string | number)[]
+>['aaa'] : string[]
+>'aaa' : "aaa"
+
+const isString = (x: unknown): x is string => typeof x === 'string';
+>isString : (x: unknown) => x is string
+>(x: unknown): x is string => typeof x === 'string' : (x: unknown) => x is string
+>x : unknown
+>typeof x === 'string' : boolean
+>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>x : unknown
+>'string' : "string"
+
+if (foo.every(isString)) {
+>foo.every(isString) : boolean
+>foo.every : { <S extends string | number>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any): boolean; }
+>foo : (string | number)[]
+>every : { <S extends string | number>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any): boolean; }
+>isString : (x: unknown) => x is string
+
+  foo[0].slice(0);
+>foo[0].slice(0) : string
+>foo[0].slice : (start?: number, end?: number) => string
+>foo[0] : string
+>foo : string[]
+>0 : 0
+>slice : (start?: number, end?: number) => string
+>0 : 0
+}
+

tests/baselines/reference/contextuallyTypedIife.symbols

@@ -47,17 +47,17 @@
 // rest parameters
 ((...numbers) => numbers.every(n => n > 0))(5,6,7);
 >numbers : Symbol(numbers, Decl(contextuallyTypedIife.ts, 17, 2))
->numbers.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>numbers.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >numbers : Symbol(numbers, Decl(contextuallyTypedIife.ts, 17, 2))
->every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >n : Symbol(n, Decl(contextuallyTypedIife.ts, 17, 31))
 >n : Symbol(n, Decl(contextuallyTypedIife.ts, 17, 31))
 
 ((...mixed) => mixed.every(n => !!n))(5,'oops','oh no');
 >mixed : Symbol(mixed, Decl(contextuallyTypedIife.ts, 18, 2))
->mixed.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>mixed.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >mixed : Symbol(mixed, Decl(contextuallyTypedIife.ts, 18, 2))
->every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >n : Symbol(n, Decl(contextuallyTypedIife.ts, 18, 27))
 >n : Symbol(n, Decl(contextuallyTypedIife.ts, 18, 27))
 

tests/baselines/reference/contextuallyTypedIife.types

@@ -105,9 +105,9 @@
 >(...numbers) => numbers.every(n => n > 0) : (numbers_0: number, numbers_1: number, numbers_2: number) => boolean
 >numbers : [number, number, number]
 >numbers.every(n => n > 0) : boolean
->numbers.every : (callbackfn: (value: number, index: number, array: number[]) => unknown, thisArg?: any) => boolean
+>numbers.every : { <S extends number>(callbackfn: (value: number, index: number, array: number[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: number, index: number, array: number[]) => unknown, thisArg?: any): boolean; }
 >numbers : [number, number, number]
->every : (callbackfn: (value: number, index: number, array: number[]) => unknown, thisArg?: any) => boolean
+>every : { <S extends number>(callbackfn: (value: number, index: number, array: number[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: number, index: number, array: number[]) => unknown, thisArg?: any): boolean; }
 >n => n > 0 : (n: number) => boolean
 >n : number
 >n > 0 : boolean
@@ -123,9 +123,9 @@
 >(...mixed) => mixed.every(n => !!n) : (mixed_0: number, mixed_1: string, mixed_2: string) => boolean
 >mixed : [number, string, string]
 >mixed.every(n => !!n) : boolean
->mixed.every : (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any) => boolean
+>mixed.every : { <S extends string | number>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any): boolean; }
 >mixed : [number, string, string]
->every : (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any) => boolean
+>every : { <S extends string | number>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any): boolean; }
 >n => !!n : (n: string | number) => boolean
 >n : string | number
 >!!n : boolean

tests/baselines/reference/contextuallyTypedIifeStrict.symbols

@@ -47,17 +47,17 @@
 // rest parameters
 ((...numbers) => numbers.every(n => n > 0))(5,6,7);
 >numbers : Symbol(numbers, Decl(contextuallyTypedIifeStrict.ts, 17, 2))
->numbers.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>numbers.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >numbers : Symbol(numbers, Decl(contextuallyTypedIifeStrict.ts, 17, 2))
->every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >n : Symbol(n, Decl(contextuallyTypedIifeStrict.ts, 17, 31))
 >n : Symbol(n, Decl(contextuallyTypedIifeStrict.ts, 17, 31))
 
 ((...mixed) => mixed.every(n => !!n))(5,'oops','oh no');
 >mixed : Symbol(mixed, Decl(contextuallyTypedIifeStrict.ts, 18, 2))
->mixed.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>mixed.every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >mixed : Symbol(mixed, Decl(contextuallyTypedIifeStrict.ts, 18, 2))
->every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --))
+>every : Symbol(Array.every, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >n : Symbol(n, Decl(contextuallyTypedIifeStrict.ts, 18, 27))
 >n : Symbol(n, Decl(contextuallyTypedIifeStrict.ts, 18, 27))
 

tests/baselines/reference/contextuallyTypedIifeStrict.types

@@ -105,9 +105,9 @@
 >(...numbers) => numbers.every(n => n > 0) : (numbers_0: number, numbers_1: number, numbers_2: number) => boolean
 >numbers : [number, number, number]
 >numbers.every(n => n > 0) : boolean
->numbers.every : (callbackfn: (value: number, index: number, array: number[]) => unknown, thisArg?: any) => boolean
+>numbers.every : { <S extends number>(callbackfn: (value: number, index: number, array: number[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: number, index: number, array: number[]) => unknown, thisArg?: any): boolean; }
 >numbers : [number, number, number]
->every : (callbackfn: (value: number, index: number, array: number[]) => unknown, thisArg?: any) => boolean
+>every : { <S extends number>(callbackfn: (value: number, index: number, array: number[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: number, index: number, array: number[]) => unknown, thisArg?: any): boolean; }
 >n => n > 0 : (n: number) => boolean
 >n : number
 >n > 0 : boolean
@@ -123,9 +123,9 @@
 >(...mixed) => mixed.every(n => !!n) : (mixed_0: number, mixed_1: string, mixed_2: string) => boolean
 >mixed : [number, string, string]
 >mixed.every(n => !!n) : boolean
->mixed.every : (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any) => boolean
+>mixed.every : { <S extends string | number>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any): boolean; }
 >mixed : [number, string, string]
->every : (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any) => boolean
+>every : { <S extends string | number>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => value is S, thisArg?: any): this is S[]; (callbackfn: (value: string | number, index: number, array: (string | number)[]) => unknown, thisArg?: any): boolean; }
 >n => !!n : (n: string | number) => boolean
 >n : string | number
 >!!n : boolean