184 lines
5.8 KiB
TypeScript
184 lines
5.8 KiB
TypeScript
//// [inferTypes1.ts]
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type Unpacked<T> =
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T extends (infer U)[] ? U :
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T extends (...args: any[]) => infer U ? U :
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T extends Promise<infer U> ? U :
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T;
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type T00 = Unpacked<string>; // string
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type T01 = Unpacked<string[]>; // string
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type T02 = Unpacked<() => string>; // string
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type T03 = Unpacked<Promise<string>>; // string
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type T04 = Unpacked<Unpacked<Promise<string>[]>>; // string
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type T05 = Unpacked<any>; // any
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type T06 = Unpacked<never>; // never
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function f1(s: string) {
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return { a: 1, b: s };
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}
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class C {
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x = 0;
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y = 0;
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}
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type T10 = ReturnType<() => string>; // string
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type T11 = ReturnType<(s: string) => void>; // void
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type T12 = ReturnType<(<T>() => T)>; // {}
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type T13 = ReturnType<(<T extends U, U extends number[]>() => T)>; // number[]
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type T14 = ReturnType<typeof f1>; // { a: number, b: string }
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type T15 = ReturnType<any>; // any
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type T16 = ReturnType<never>; // never
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type T17 = ReturnType<string>; // Error
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type T18 = ReturnType<Function>; // Error
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type U10 = InstanceType<typeof C>; // C
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type U11 = InstanceType<any>; // any
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type U12 = InstanceType<never>; // never
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type U13 = InstanceType<string>; // Error
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type U14 = InstanceType<Function>; // Error
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type ArgumentType<T extends (x: any) => any> = T extends (a: infer A) => any ? A : any;
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type T20 = ArgumentType<() => void>; // {}
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type T21 = ArgumentType<(x: string) => number>; // string
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type T22 = ArgumentType<(x?: string) => number>; // string | undefined
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type T23 = ArgumentType<(...args: string[]) => number>; // string
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type T24 = ArgumentType<(x: string, y: string) => number>; // Error
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type T25 = ArgumentType<Function>; // Error
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type T26 = ArgumentType<any>; // any
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type T27 = ArgumentType<never>; // never
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type X1<T extends { x: any, y: any }> = T extends { x: infer X, y: infer Y } ? [X, Y] : any;
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type T30 = X1<{ x: any, y: any }>; // [any, any]
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type T31 = X1<{ x: number, y: string }>; // [number, string]
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type T32 = X1<{ x: number, y: string, z: boolean }>; // [number, string]
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type X2<T> = T extends { a: infer U, b: infer U } ? U : never;
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type T40 = X2<{}>; // never
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type T41 = X2<{ a: string }>; // never
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type T42 = X2<{ a: string, b: string }>; // string
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type T43 = X2<{ a: number, b: string }>; // string | number
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type T44 = X2<{ a: number, b: string, c: boolean }>; // string | number
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type X3<T> = T extends { a: (x: infer U) => void, b: (x: infer U) => void } ? U : never;
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type T50 = X3<{}>; // never
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type T51 = X3<{ a: (x: string) => void }>; // never
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type T52 = X3<{ a: (x: string) => void, b: (x: string) => void }>; // string
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type T53 = X3<{ a: (x: number) => void, b: (x: string) => void }>; // string & number
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type T54 = X3<{ a: (x: number) => void, b: () => void }>; // number
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type T60 = infer U; // Error
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type T61<T> = infer A extends infer B ? infer C : infer D; // Error
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type T62<T> = U extends (infer U)[] ? U : U; // Error
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type T63<T> = T extends (infer A extends infer B ? infer C : infer D) ? string : number;
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type T70<T extends string> = { x: T };
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type T71<T> = T extends T70<infer U> ? T70<U> : never;
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type T72<T extends number> = { y: T };
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type T73<T> = T extends T72<infer U> ? T70<U> : never; // Error
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type T74<T extends number, U extends string> = { x: T, y: U };
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type T75<T> = T extends T74<infer U, infer U> ? T70<U> | T72<U> | T74<U, U> : never;
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type T76<T extends T[], U extends T> = { x: T };
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type T77<T> = T extends T76<infer X, infer Y> ? T76<X, Y> : never;
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type T78<T> = T extends T76<infer X, infer X> ? T76<X, X> : never;
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type Foo<T extends string, U extends T> = [T, U];
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type Bar<T> = T extends Foo<infer X, infer Y> ? Foo<X, Y> : never;
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type T90 = Bar<[string, string]>; // [string, string]
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type T91 = Bar<[string, "a"]>; // [string, "a"]
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type T92 = Bar<[string, "a"] & { x: string }>; // [string, "a"]
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type T93 = Bar<["a", string]>; // never
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type T94 = Bar<[number, number]>; // never
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// Example from #21496
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type JsonifiedObject<T extends object> = { [K in keyof T]: Jsonified<T[K]> };
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type Jsonified<T> =
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T extends string | number | boolean | null ? T
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: T extends undefined | Function ? never // undefined and functions are removed
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: T extends { toJSON(): infer R } ? R // toJSON is called if it exists (e.g. Date)
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: T extends object ? JsonifiedObject<T>
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: "what is this";
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type Example = {
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str: "literalstring",
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fn: () => void,
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date: Date,
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customClass: MyClass,
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obj: {
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prop: "property",
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clz: MyClass,
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nested: { attr: Date }
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},
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}
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declare class MyClass {
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toJSON(): "correct";
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}
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type JsonifiedExample = Jsonified<Example>;
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declare let ex: JsonifiedExample;
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const z1: "correct" = ex.customClass;
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const z2: string = ex.obj.nested.attr;
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// Repros from #21631
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type A1<T, U extends A1<any, any>> = [T, U];
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type B1<S> = S extends A1<infer T, infer U> ? [T, U] : never;
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type A2<T, U extends void> = [T, U];
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type B2<S> = S extends A2<infer T, infer U> ? [T, U] : never;
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type C2<S, U extends void> = S extends A2<infer T, U> ? [T, U] : never;
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// Repro from #21735
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type A<T> = T extends string ? { [P in T]: void; } : T;
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type B<T> = string extends T ? { [P in T]: void; } : T; // Error
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// Repro from #22302
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type MatchingKeys<T, U, K extends keyof T = keyof T> =
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K extends keyof T ? T[K] extends U ? K : never : never;
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type VoidKeys<T> = MatchingKeys<T, void>;
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interface test {
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a: 1,
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b: void
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}
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type T80 = MatchingKeys<test, void>;
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type T81 = VoidKeys<test>;
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// Repro from #22221
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type MustBeString<T extends string> = T;
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type EnsureIsString<T> = T extends MustBeString<infer U> ? U : never;
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type Test1 = EnsureIsString<"hello">; // "hello"
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type Test2 = EnsureIsString<42>; // never
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//// [inferTypes1.js]
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"use strict";
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function f1(s) {
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return { a: 1, b: s };
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}
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var C = /** @class */ (function () {
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function C() {
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this.x = 0;
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this.y = 0;
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}
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return C;
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}());
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var z1 = ex.customClass;
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var z2 = ex.obj.nested.attr;
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