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Unlimited Array.prototype.flat depth #55686

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7ff6d79
Unlimited depth Array.prototype.flat definitionion
Sep 8, 2023
daf057b
Baseline accept
Sep 8, 2023
a983d8f
Test array flat unlimited depth
Sep 8, 2023
2bfc73b
Rename helper type
Sep 8, 2023
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21 changes: 16 additions & 5 deletions src/lib/es2019.array.d.ts
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@@ -1,8 +1,19 @@
type FlatArray<Arr, Depth extends number> = {
done: Arr;
recur: Arr extends ReadonlyArray<infer InnerArr> ? FlatArray<InnerArr, [-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20][Depth]>
: Arr;
}[Depth extends -1 ? "done" : "recur"];
type Integer = any[];

type Increment<N extends Integer> = [...N, any];

type FlattenArrayByOneLevel <Arr> = Arr extends ReadonlyArray<infer InnerArr> ? InnerArr : Arr;

type FlatArray<Arr, Depth extends number, Counter extends Integer = []> =
Arr extends ReadonlyArray<any>
? (
Counter['length'] extends 999
? unknown
: Counter['length'] extends Depth
? FlattenArrayByOneLevel<Arr>
: FlatArray<FlattenArrayByOneLevel<Arr>, Depth, Increment<Counter>>
)
: Arr;

interface ReadonlyArray<T> {
/**
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8 changes: 4 additions & 4 deletions tests/baselines/reference/arrayFlatNoCrashInference.types
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Expand Up @@ -2,14 +2,14 @@

=== arrayFlatNoCrashInference.ts ===
function foo<T>(arr: T[], depth: number) {
>foo : <T>(arr: T[], depth: number) => FlatArray<T, 0 | 1 | -1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20>[]
>foo : <T>(arr: T[], depth: number) => T[]
>arr : T[]
>depth : number

return arr.flat(depth);
>arr.flat(depth) : FlatArray<T, 0 | 1 | -1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20>[]
>arr.flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D>[]
>arr.flat(depth) : T[]
>arr.flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D, []>[]
>arr : T[]
>flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D>[]
>flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D, []>[]
>depth : number
}
2 changes: 1 addition & 1 deletion tests/baselines/reference/arrayFlatNoCrashInferenceDeclarations.js
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Expand Up @@ -13,4 +13,4 @@ function foo(arr, depth) {


//// [arrayFlatNoCrashInferenceDeclarations.d.ts]
declare function foo<T>(arr: T[], depth: number): FlatArray<T, 0 | 1 | -1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20>[];
declare function foo<T>(arr: T[], depth: number): T[];
8 changes: 4 additions & 4 deletions tests/baselines/reference/arrayFlatNoCrashInferenceDeclarations.types
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Expand Up @@ -2,14 +2,14 @@

=== arrayFlatNoCrashInferenceDeclarations.ts ===
function foo<T>(arr: T[], depth: number) {
>foo : <T>(arr: T[], depth: number) => FlatArray<T, 0 | 1 | -1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20>[]
>foo : <T>(arr: T[], depth: number) => T[]
>arr : T[]
>depth : number

return arr.flat(depth);
>arr.flat(depth) : FlatArray<T, 0 | 1 | -1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20>[]
>arr.flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D>[]
>arr.flat(depth) : T[]
>arr.flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D, []>[]
>arr : T[]
>flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D>[]
>flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D, []>[]
>depth : number
}
11 changes: 11 additions & 0 deletions tests/baselines/reference/arrayFlatUnlimitedDepth.js
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@@ -0,0 +1,11 @@
//// [tests/cases/compiler/arrayFlatUnlimitedDepth.ts] ////

//// [arrayFlatUnlimitedDepth.ts]
const foo = [ [ ['string' ] ] ]
const flatFoo : string[] = foo.flat(1000)


//// [arrayFlatUnlimitedDepth.js]
"use strict";
var foo = [[['string']]];
var flatFoo = foo.flat(1000);
12 changes: 12 additions & 0 deletions tests/baselines/reference/arrayFlatUnlimitedDepth.symbols
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@@ -0,0 +1,12 @@
//// [tests/cases/compiler/arrayFlatUnlimitedDepth.ts] ////

=== arrayFlatUnlimitedDepth.ts ===
const foo = [ [ ['string' ] ] ]
>foo : Symbol(foo, Decl(arrayFlatUnlimitedDepth.ts, 0, 5))

const flatFoo : string[] = foo.flat(1000)
>flatFoo : Symbol(flatFoo, Decl(arrayFlatUnlimitedDepth.ts, 1, 5))
>foo.flat : Symbol(Array.flat, Decl(lib.es2019.array.d.ts, --, --))
>foo : Symbol(foo, Decl(arrayFlatUnlimitedDepth.ts, 0, 5))
>flat : Symbol(Array.flat, Decl(lib.es2019.array.d.ts, --, --))

18 changes: 18 additions & 0 deletions tests/baselines/reference/arrayFlatUnlimitedDepth.types
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@@ -0,0 +1,18 @@
//// [tests/cases/compiler/arrayFlatUnlimitedDepth.ts] ////

=== arrayFlatUnlimitedDepth.ts ===
const foo = [ [ ['string' ] ] ]
>foo : string[][][]
>[ [ ['string' ] ] ] : string[][][]
>[ ['string' ] ] : string[][]
>['string' ] : string[]
>'string' : "string"

const flatFoo : string[] = foo.flat(1000)
>flatFoo : string[]
>foo.flat(1000) : string[]
>foo.flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D, []>[]
>foo : string[][][]
>flat : <A, D extends number = 1>(this: A, depth?: D | undefined) => FlatArray<A, D, []>[]
>1000 : 1000

2 changes: 1 addition & 1 deletion tests/baselines/reference/declarationEmitDistributiveConditionalWithInfer.js
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Expand Up @@ -17,4 +17,4 @@ exports.fun = fun;


//// [declarationEmitDistributiveConditionalWithInfer.d.ts]
export declare const fun: (subFun: <Collection, Field extends keyof Collection>() => (Collection[Field] extends infer T ? T extends Collection[Field] ? T extends readonly (infer InnerArr)[] ? InnerArr : T : never : never)[]) => void;
export declare const fun: (subFun: <Collection, Field extends keyof Collection>() => FlatArray<Collection[Field], 0, []>[]) => void;
6 changes: 3 additions & 3 deletions tests/baselines/reference/declarationEmitDistributiveConditionalWithInfer.types
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Expand Up @@ -3,11 +3,11 @@
=== declarationEmitDistributiveConditionalWithInfer.ts ===
// This function's type is changed on declaration
export const fun = (
>fun : (subFun: <Collection, Field extends keyof Collection>() => (Collection[Field] extends readonly (infer InnerArr)[] ? InnerArr : Collection[Field])[]) => void
>( subFun: <Collection, Field extends keyof Collection>() => FlatArray<Collection[Field], 0>[]) => { } : (subFun: <Collection, Field extends keyof Collection>() => (Collection[Field] extends readonly (infer InnerArr)[] ? InnerArr : Collection[Field])[]) => void
>fun : (subFun: <Collection, Field extends keyof Collection>() => FlatArray<Collection[Field], 0, []>[]) => void
>( subFun: <Collection, Field extends keyof Collection>() => FlatArray<Collection[Field], 0>[]) => { } : (subFun: <Collection, Field extends keyof Collection>() => FlatArray<Collection[Field], 0, []>[]) => void

subFun: <Collection, Field extends keyof Collection>()
>subFun : <Collection, Field extends keyof Collection>() => (Collection[Field] extends readonly (infer InnerArr)[] ? InnerArr : Collection[Field])[]
>subFun : <Collection, Field extends keyof Collection>() => FlatArray<Collection[Field], 0, []>[]

=> FlatArray<Collection[Field], 0>[]) => { };

44 changes: 0 additions & 44 deletions tests/baselines/reference/flatArrayNoExcessiveStackDepth.errors.txt
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This file was deleted.

16 changes: 8 additions & 8 deletions tests/baselines/reference/flatArrayNoExcessiveStackDepth.types
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Expand Up @@ -56,17 +56,17 @@ const repro_43249 = (value: unknown) => {

function f<Arr, D extends number>(x: FlatArray<Arr, any>, y: FlatArray<Arr, D>) {
>f : <Arr, D extends number>(x: FlatArray<Arr, any>, y: FlatArray<Arr, D>) => void
>x : FlatArray<Arr, any>
>y : FlatArray<Arr, D>
>x : FlatArray<Arr, any, []>
>y : FlatArray<Arr, D, []>

x = y;
>x = y : FlatArray<Arr, D>
>x : FlatArray<Arr, any>
>y : FlatArray<Arr, D>
>x = y : FlatArray<Arr, D, []>
>x : FlatArray<Arr, any, []>
>y : FlatArray<Arr, D, []>

y = x; // Error
>y = x : Arr extends readonly (infer InnerArr)[] ? FlatArray<InnerArr, 0 | 2 | 1 | -1 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20> : Arr
>y : FlatArray<Arr, D>
>x : Arr extends readonly (infer InnerArr)[] ? FlatArray<InnerArr, 0 | 2 | 1 | -1 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20> : Arr
>y = x : FlatArray<Arr, any, []>
>y : FlatArray<Arr, D, []>
>x : FlatArray<Arr, any, []>
}

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