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Get Optional

提出詳細

type IsOptional<T, K extends PropertyKey> = Omit<T, K> extends T ? true : false

type GetOptional<T> = {
  [K in keyof T as IsOptional<T, K> extends true ? K : never]: T[K]
}
提出日時2023-08-13 12:16:45
問題Get Optional
ユーザーtekihei2317
ステータスAccepted
テストケース
import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<GetOptional<{ foo: number; bar?: string }>, { bar?: string }>>,
  Expect<Equal<GetOptional<{ foo: undefined; bar?: undefined }>, { bar?: undefined }>>,
]