L0v3ch4n

外观

Slice

约 203 字小于 1 分钟

2026-02-11

题目

Implement the JavaScript Array.slice function in the type system. Slice<Arr, Start, End> takes the three argument. The output should be a subarray of Arr from index Start to End. Indexes with negative numbers should be counted from reversely.

For example

type Arr = [1, 2, 3, 4, 5]
type Result = Slice<Arr, 2, 4> // expected to be [3, 4]

解题思路

待补充

答案

type Slice<Arr, Start, End> = any

验证

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

type Arr = [1, 2, 3, 4, 5]

type cases = [
  // basic
  Expect<Equal<Slice<Arr, 0, 1>, [1]>>,
  Expect<Equal<Slice<Arr, 0, 0>, []>>,
  Expect<Equal<Slice<Arr, 2, 4>, [3, 4]>>,

  // optional args
  Expect<Equal<Slice<[]>, []>>,
  Expect<Equal<Slice<Arr>, Arr>>,
  Expect<Equal<Slice<Arr, 0>, Arr>>,
  Expect<Equal<Slice<Arr, 2>, [3, 4, 5]>>,

  // negative index
  Expect<Equal<Slice<Arr, 0, -1>, [1, 2, 3, 4]>>,
  Expect<Equal<Slice<Arr, -3, -1>, [3, 4]>>,

  // invalid
  Expect<Equal<Slice<Arr, 10>, []>>,
  Expect<Equal<Slice<Arr, 1, 0>, []>>,
  Expect<Equal<Slice<Arr, 10, 20>, []>>,
]

参考

无