L0v3ch4n

外观

Append to object

约 184 字小于 1 分钟

2026-02-11

题目

实现一个为接口添加一个新字段的类型。该类型接收三个参数，返回带有新字段的接口类型。

例如:

type Test = { id: '1' }
type Result = AppendToObject<Test, 'value', 4> // expected to be { id: '1', value: 4 }

解题思路

待补充

答案

type AppendToObject<T, U, V> = any

验证

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

type test1 = {
  key: 'cat'
  value: 'green'
}

type testExpect1 = {
  key: 'cat'
  value: 'green'
  home: boolean
}

type test2 = {
  key: 'dog' | undefined
  value: 'white'
  sun: true
}

type testExpect2 = {
  key: 'dog' | undefined
  value: 'white'
  sun: true
  home: 1
}

type test3 = {
  key: 'cow'
  value: 'yellow'
  sun: false
}

type testExpect3 = {
  key: 'cow'
  value: 'yellow'
  sun: false
  moon: false | undefined
}

type cases = [
  Expect<Equal<AppendToObject<test1, 'home', boolean>, testExpect1>>,
  Expect<Equal<AppendToObject<test2, 'home', 1>, testExpect2>>,
  Expect<Equal<AppendToObject<test3, 'moon', false | undefined>, testExpect3>>,
]

参考

无