Promise.all
约 211 字小于 1 分钟
2026-02-11
题目
给函数PromiseAll指定类型,它接受元素为 Promise 或者类似 Promise 的对象的数组,返回值应为Promise<T>,其中T是这些 Promise 的结果组成的数组。
const promise1 = Promise.resolve(3);
const promise2 = 42;
const promise3 = new Promise<string>((resolve, reject) => {
setTimeout(resolve, 100, 'foo');
});
// 应推导出 `Promise<[number, 42, string]>`
const p = PromiseAll([promise1, promise2, promise3] as const)解题思路
待补充
答案
declare function PromiseAll(values: any): any验证
import type { Equal, Expect } from '@type-challenges/utils'
const promiseAllTest1 = PromiseAll([1, 2, 3] as const)
const promiseAllTest2 = PromiseAll([1, 2, Promise.resolve(3)] as const)
const promiseAllTest3 = PromiseAll([1, 2, Promise.resolve(3)])
const promiseAllTest4 = PromiseAll<Array<number | Promise<number>>>([1, 2, 3])
const promiseAllTest5 = PromiseAll<(number | Promise<string>)[]>([1, 2, Promise.resolve('3')])
type cases = [
Expect<Equal<typeof promiseAllTest1, Promise<[1, 2, 3]>>>,
Expect<Equal<typeof promiseAllTest2, Promise<[1, 2, number]>>>,
Expect<Equal<typeof promiseAllTest3, Promise<[number, number, number]>>>,
Expect<Equal<typeof promiseAllTest4, Promise<number[]>>>,
Expect<Equal<typeof promiseAllTest5, Promise<(number | string)[]>>>,
]参考
无
