by Anthony Fu @antfu
Type the function PromiseAll that accepts an array of PromiseLike objects, the returning value should be Promise<T> where T is the resolved result array.
const promise1 = Promise.resolve(3);
const promise2 = 42;
const promise3 = new Promise<string>((resolve, reject) => {
setTimeout(resolve, 100, 'foo');
});
// expected to be `Promise<[number, number, string]>`
const p = Promise.all([promise1, promise2, promise3] as const)
