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Length of Tuple

提出詳細

type Length<T extends readonly any[]> = 
  T extends readonly [any, any, any, any] ? 4
  : T extends readonly [any, any, any, any, any] ? 5
  : never
提出日時2023-08-26 05:43:55
問題Length of Tuple
ユーザーsnaka
ステータスAccepted
テストケース
import type { Equal, Expect } from '@type-challenges/utils'

const tesla = ['tesla', 'model 3', 'model X', 'model Y'] as const
const spaceX = ['FALCON 9', 'FALCON HEAVY', 'DRAGON', 'STARSHIP', 'HUMAN SPACEFLIGHT'] as const

type cases = [
  Expect<Equal<Length<typeof tesla>, 4>>,
  Expect<Equal<Length<typeof spaceX>, 5>>,
  // @ts-expect-error
  Length<5>,
  // @ts-expect-error
  Length<'hello world'>,
]