Type Challenges Judge

First of Array

提出詳細

type First<Arr extends unknown[]> = Arr extends [] ? never : Arr[0];
提出日時2023-05-17 14:19:45
問題First of Array
ユーザーmrsekut
ステータスAccepted
テストケース
import type { Equal, Expect } from '@type-challenges/utils' type cases = [ Expect<Equal<First<[3, 2, 1]>, 3>>, Expect<Equal<First<[() => 123, { a: string }]>, () => 123>>, Expect<Equal<First<[]>, never>>, Expect<Equal<First<[undefined]>, undefined>>, ] type errors = [ // @ts-expect-error First<'notArray'>, // @ts-expect-error First<{ 0: 'arrayLike' }>, ]