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Fix issue with Array#flatMap callback return type

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Closes #22685
This commit is contained in:
Rhys van der Waerden
2018-08-01 16:44:53 +10:00
parent 9c9f3e3cf9
commit 23640d971b
5 changed files with 65 additions and 2 deletions
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4
src/lib/esnext.array.d.ts vendored
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@@ -11,7 +11,7 @@ interface ReadonlyArray<T> {
* thisArg is omitted, undefined is used as the this value.
*/
flatMap<U, This = undefined> (
callback: (this: This, value: T, index: number, array: T[]) => U|U[],
callback: (this: This, value: T, index: number, array: T[]) => U|ReadonlyArray<U>,
thisArg?: This
): U[]
@@ -125,7 +125,7 @@ interface Array<T> {
* thisArg is omitted, undefined is used as the this value.
*/
flatMap<U, This = undefined> (
callback: (this: This, value: T, index: number, array: T[]) => U|U[],
callback: (this: This, value: T, index: number, array: T[]) => U|ReadonlyArray<U>,
thisArg?: This
): U[]

12
tests/baselines/reference/arrayFlatMap.js Normal file
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@@ -0,0 +1,12 @@
//// [arrayFlatMap.ts]
const array: number[] = [];
const readonlyArray: ReadonlyArray<number> = [];
array.flatMap((): ReadonlyArray<number> => []); // ok
readonlyArray.flatMap((): ReadonlyArray<number> => []); // ok
//// [arrayFlatMap.js]
var array = [];
var readonlyArray = [];
array.flatMap(function () { return []; }); // ok
readonlyArray.flatMap(function () { return []; }); // ok

20
tests/baselines/reference/arrayFlatMap.symbols Normal file
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@@ -0,0 +1,20 @@
=== tests/cases/compiler/arrayFlatMap.ts ===
const array: number[] = [];
>array : Symbol(array, Decl(arrayFlatMap.ts, 0, 5))
const readonlyArray: ReadonlyArray<number> = [];
>readonlyArray : Symbol(readonlyArray, Decl(arrayFlatMap.ts, 1, 5))
>ReadonlyArray : Symbol(ReadonlyArray, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2016.array.include.d.ts, --, --), Decl(lib.esnext.array.d.ts, --, --))
array.flatMap((): ReadonlyArray<number> => []); // ok
>array.flatMap : Symbol(Array.flatMap, Decl(lib.esnext.array.d.ts, --, --))
>array : Symbol(array, Decl(arrayFlatMap.ts, 0, 5))
>flatMap : Symbol(Array.flatMap, Decl(lib.esnext.array.d.ts, --, --))
>ReadonlyArray : Symbol(ReadonlyArray, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2016.array.include.d.ts, --, --), Decl(lib.esnext.array.d.ts, --, --))
readonlyArray.flatMap((): ReadonlyArray<number> => []); // ok
>readonlyArray.flatMap : Symbol(ReadonlyArray.flatMap, Decl(lib.esnext.array.d.ts, --, --))
>readonlyArray : Symbol(readonlyArray, Decl(arrayFlatMap.ts, 1, 5))
>flatMap : Symbol(ReadonlyArray.flatMap, Decl(lib.esnext.array.d.ts, --, --))
>ReadonlyArray : Symbol(ReadonlyArray, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2016.array.include.d.ts, --, --), Decl(lib.esnext.array.d.ts, --, --))

25
tests/baselines/reference/arrayFlatMap.types Normal file
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@@ -0,0 +1,25 @@
=== tests/cases/compiler/arrayFlatMap.ts ===
const array: number[] = [];
>array : number[]
>[] : undefined[]
const readonlyArray: ReadonlyArray<number> = [];
>readonlyArray : ReadonlyArray<number>
>[] : undefined[]
array.flatMap((): ReadonlyArray<number> => []); // ok
>array.flatMap((): ReadonlyArray<number> => []) : number[]
>array.flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | ReadonlyArray<U>, thisArg?: This) => U[]
>array : number[]
>flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | ReadonlyArray<U>, thisArg?: This) => U[]
>(): ReadonlyArray<number> => [] : () => ReadonlyArray<number>
>[] : undefined[]
readonlyArray.flatMap((): ReadonlyArray<number> => []); // ok
>readonlyArray.flatMap((): ReadonlyArray<number> => []) : number[]
>readonlyArray.flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | ReadonlyArray<U>, thisArg?: This) => U[]
>readonlyArray : ReadonlyArray<number>
>flatMap : <U, This = undefined>(callback: (this: This, value: number, index: number, array: number[]) => U | ReadonlyArray<U>, thisArg?: This) => U[]
>(): ReadonlyArray<number> => [] : () => ReadonlyArray<number>
>[] : undefined[]

6
tests/cases/compiler/arrayFlatMap.ts Normal file
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@@ -0,0 +1,6 @@
// @lib: esnext
const array: number[] = [];
const readonlyArray: ReadonlyArray<number> = [];
array.flatMap((): ReadonlyArray<number> => []); // ok
readonlyArray.flatMap((): ReadonlyArray<number> => []); // ok