[Typescript] 13. Easy - Unshift

Implement the type version of Array.unshift

For example:

type Result = Unshift<[1, 2], 0> // [0, 1, 2,]

 

/* _____________ Your Code Here _____________ */

type Unshift<T extends unknown[], U> = [
  U,
  ...T
]


/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<Unshift<[], 1>, [1]>>,
  Expect<Equal<Unshift<[1, 2], 0>, [0, 1, 2]>>,
  Expect<Equal<Unshift<['1', 2, '3'], boolean>, [boolean, '1', 2, '3']>>,
]

 

posted @ 2022-09-03 23:34  Zhentiw  阅读(16)  评论(0编辑  收藏  举报