18142. All

<题目描述>

::: playground#ts 18142. All

@file index.ts

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

type cases = [
  Expect<Equal<All<[1, 1, 1], 1>, true>>,
  Expect<Equal<All<[1, 1, 2], 1>, false>>,
  Expect<Equal<All<['1', '1', '1'], '1'>, true>>,
  Expect<Equal<All<['1', '1', '1'], 1>, false>>,
  Expect<Equal<All<[number, number, number], number>, true>>,
  Expect<Equal<All<[number, number, string], number>, false>>,
  Expect<Equal<All<[null, null, null], null>, true>>,
  Expect<Equal<All<[[1], [1], [1]], [1]>, true>>,
  Expect<Equal<All<[{}, {}, {}], {}>, true>>,
  Expect<Equal<All<[never], never>, true>>,
  Expect<Equal<All<[any], any>, true>>,
  Expect<Equal<All<[unknown], unknown>, true>>,
  Expect<Equal<All<[any], unknown>, false>>,
  Expect<Equal<All<[unknown], any>, false>>,
]

// ============= Your Code Here =============
type All<T extends any[], U> = any

:::

点击查看答案

type All<T extends any[], U> = T extends [infer F, ...infer R] ?
  Equal<F, U> extends true ? All<R, U> : false : true