24 lines
992 B
TypeScript
24 lines
992 B
TypeScript
//// [computedTypesKeyofNoIndexSignatureType.ts]
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type Compute<A> = { [K in keyof A]: Compute<A[K]>; } & {};
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type EqualsTest<T> = <A>() => A extends T ? 1 : 0;
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type Equals<A1, A2> = EqualsTest<A2> extends EqualsTest<A1> ? 1 : 0;
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type Filter<K, I> = Equals<K, I> extends 1 ? never : K;
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type OmitIndex<T, I extends string | number> = {
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[K in keyof T as Filter<K, I>]: T[K];
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};
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type IndexObject = { [key: string]: unknown; };
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type FooBar = { foo: "hello"; bar: "world"; };
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type WithIndex = Compute<FooBar & IndexObject>; // { [x: string]: {}; foo: "hello"; bar: "world"; } <-- OK
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type WithoutIndex = OmitIndex<WithIndex, string>; // { foo: "hello"; bar: "world"; } <-- OK
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type FooBarKey = keyof FooBar; // "foo" | "bar" <-- OK
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type WithIndexKey = keyof WithIndex; // string | number <-- Expected: string
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type WithoutIndexKey = keyof WithoutIndex; // number <-- Expected: "foo" | "bar"
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//// [computedTypesKeyofNoIndexSignatureType.js]
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