5140 - Trunc

5140 - Trunc

by jiangshan (@jiangshanmeta) #中等 #template-literal

题目

Implement the type version of Math.trunc, which takes string or number and returns the integer part of a number by removing any fractional digits.

For example:

type A = Trunc<12.34> // 12

在 Github 上查看：https://tsch.js.org/5140/zh-CN

代码

/* _____________ 你的代码 _____________ */

type Trunc<T extends number | string> = `${T}` extends `${infer F}.${string}`
  ? F extends ''
    ? '0'
    : F extends '-'
      ? '-0'
      : F
  : `${T}`

测试用例

/* _____________ 测试用例 _____________ */
import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<Trunc<0.1>, '0'>>,
  Expect<Equal<Trunc<0.2>, '0'>>,
  Expect<Equal<Trunc<1.234>, '1'>>,
  Expect<Equal<Trunc<12.345>, '12'>>,
  Expect<Equal<Trunc<-5.1>, '-5'>>,
  Expect<Equal<Trunc<'.3'>, '0'>>,
  Expect<Equal<Trunc<'1.234'>, '1'>>,
  Expect<Equal<Trunc<'-.3'>, '-0'>>,
  Expect<Equal<Trunc<'-10.234'>, '-10'>>,
  Expect<Equal<Trunc<10>, '10'>>,
]

相关链接

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