type-challenges-judge

Type Challenges Judge

Problems

Progress

Optional Keys

提出詳細

type OptionalKeys<T> = keyof { [P in keyof T as Partial<Pick<T, P>> extends Pick<T, P> ? P : never]: T[P] }

提出日時	2024-09-12 08:04:47
問題	Optional Keys
ユーザー	ookkoouu
ステータス	Accepted

テストケース

import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<OptionalKeys<{ a: number; b?: string }>, 'b'>>,
  Expect<Equal<OptionalKeys<{ a: undefined; b?: undefined }>, 'b'>>,
  Expect<Equal<OptionalKeys<{ a: undefined; b?: undefined; c?: string; d?: null }>, 'b' | 'c' | 'd'>>,
  Expect<Equal<OptionalKeys<{}>, never>>,
]