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@HelveticaScenario

HelveticaScenario/keysOfType.ts

Created March 12, 2020 23:16
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A type alias for getting a union of keys of an interface that match a type
Raw
keysOfType.ts
type MapKeys<R, T> = {
[P in keyof R]: R[P] extends T ? P : never;
};
type KeysOfType<R, T, IncludeOptional extends boolean = true> = Exclude<
MapKeys<R, IncludeOptional extends true ? T | undefined : T>[keyof R],
undefined
>;
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