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IndexOf

提出詳細

type MyEqual<T,U> =
  (<X>() => X extends T ? 0 : 1) extends
  (<X>() => X extends U ? 0 : 1) ? true : false
type IndexOf<T, U, Count extends readonly unknown[]=[]> =
  T extends [infer T1, ...infer T2]
  ? MyEqual<T1,U> extends true
    ? Count["length"]
    : IndexOf<T2,U,[...Count, 0]>
  : -1
提出日時2023-09-18 07:48:14
問題IndexOf
ユーザーsankantsu
ステータスAccepted
テストケース
import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<IndexOf<[1, 2, 3], 2>, 1>>,
  Expect<Equal<IndexOf<[2, 6, 3, 8, 4, 1, 7, 3, 9], 3>, 2>>,
  Expect<Equal<IndexOf<[0, 0, 0], 2>, -1>>,
  Expect<Equal<IndexOf<[string, 1, number, 'a'], number>, 2>>,
  Expect<Equal<IndexOf<[string, 1, number, 'a', any], any>, 4>>,
]