2595 - PickByType

2595 - PickByType

by jiangshan (@jiangshanmeta) #中等 #object

题目

From T, pick a set of properties whose type are assignable to U.

For Example

type OnlyBoolean = PickByType<{
  name: string
  count: number
  isReadonly: boolean
  isEnable: boolean
}, boolean> // { isReadonly: boolean; isEnable: boolean; }

在 Github 上查看：https://tsch.js.org/2595/zh-CN

代码

/* _____________ 你的代码 _____________ */

type PickByType<T, U> = {
  [K in keyof T as T[K] extends U ? K : never]: T[K]
}

测试用例

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

interface Model {
  name: string
  count: number
  isReadonly: boolean
  isEnable: boolean
}

type cases = [
  Expect<Equal<PickByType<Model, boolean>, { isReadonly: boolean, isEnable: boolean }>>,
  Expect<Equal<PickByType<Model, string>, { name: string }>>,
  Expect<Equal<PickByType<Model, number>, { count: number }>>,
]

相关链接

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