Feature request: KeysMatching (filtered keyof)

[vincerubinetti]

type KeysMatching<Obj, Type> = {
  [Key in keyof Obj]-?: Key extends Type ? Key : never;
}[keyof Obj];

Quick way to get keys of an object matching a particular patterns, e.g. template literal types. Could be useful for composing with other util types like ValueOf.

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[sindresorhus]

Could you include an example use-case (code)?

[vincerubinetti]

const data = {
  property: "123";
  project: "abc";
  topRegions: SomeComplexTypeA;
  topContinents: SomeComplexTypeB;
  topCountries: SomeComplexTypeC;
}
type Data = typeof data;
type Top = ValueOf<Data, KeysMatching<Data, `top${string}`>>;
// SomeComplexTypeA | SomeComplexTypeB | SomeComplexTypeC

[vincerubinetti]

I could do a PR if you want

[Emiyaaaaa]

I perfer split this to two type: ObjectKeys and Match(or other name). These both are useful type, and both work well in combination with other types.

[Mouvedia]

Is this a duplicate of #630? (ignoring -?)