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[Typescript Challenges] 146 Medium - CheckRepeatedTuple

发布时间 2023-07-17 01:59:37作者: Zhentiw

Implement type CheckRepeatedChars<T> which will return whether type T contains duplicated member

For example:

type CheckRepeatedTuple<[1, 2, 3]>   // false
type CheckRepeatedTuple<[1, 2, 1]>   // true

 

/* _____________ Your Code Here _____________ */
export type Includes<T extends readonly any[], U> = T extends [
  infer F,
  ...infer RT
]
  ? Equal<F, U> extends true
    ? true
    : Includes<RT, U>
  : false;
type CheckRepeatedTuple<T extends unknown[]> = T extends [infer Check, ...infer REST] ? Includes<REST, Check> : false;

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

type cases = [
  Expect<Equal<CheckRepeatedTuple<[number, number, string, boolean]>, true>>,
  Expect<Equal<CheckRepeatedTuple<[number, string]>, false>>,
  Expect<Equal<CheckRepeatedTuple<[1, 2, 3]>, false>>,
  Expect<Equal<CheckRepeatedTuple<[1, 2, 1]>, true>>,
  Expect<Equal<CheckRepeatedTuple<[]>, false>>,
  Expect<Equal<CheckRepeatedTuple<string[]>, false>>,
]