Promise.all

题目

定义函数PromiseAll，它接受PromiseLike对象数组，返回值应为Promise<T>，其中T是解析的结果数组。

const promise1 = Promise.resolve(3);
const promise2 = 42;
const promise3 = new Promise<string>((resolve, reject) => {
  setTimeout(resolve, 100, 'foo');
});

// expected to be `Promise<[number, 42, string]>`
const p = Promise.all([promise1, promise2, promise3] as const)

题目来源：https://tsch.js.org/20/zh-CN

解答

declare function PromiseAll<T extends any[]>(values: readonly [...T]): Promise<{
  [K in keyof T]: T[K] extends Promise<infer U> ? U : T[K]
}>