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02757-medium-partialbykeys
Medium
object

挑战来源: type-challenges/02757-medium-partialbykeys

实现一个通用的PartialByKeys<T, K>，它接收两个类型参数T和K。

K指定应设置为可选的T的属性集。当没有提供K时，它就和普通的Partial<T>一样使所有属性都是可选的。

例如:

interface User {
  name: string
  age: number
  address: string
}

type UserPartialName = PartialByKeys<User, 'name'> // { name?:string; age:number; address:string }

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测试用例来源: type-challenges/02757-medium-partialbykeys/test-cases.ts
import type { Equal, Expect } from '@type-challenges/utils'

interface User {
  name: string
  age: number
  address: string
}

interface UserPartialName {
  name?: string
  age: number
  address: string
}

interface UserPartialNameAndAge {
  name?: string
  age?: number
  address: string
}

type cases = [
  Expect<Equal<PartialByKeys<User, 'name'>, UserPartialName>>,
  Expect<Equal<PartialByKeys<User, 'name' | 'age'>, UserPartialNameAndAge>>,
  Expect<Equal<PartialByKeys<User>, Partial<User>>>,
  // @ts-expect-error
  Expect<Equal<PartialByKeys<User, 'name' | 'unknown'>, UserPartialName>>,
]