2636. Promise Pool

https://leetcode.com/problems/promise-pool/

Javascript

var promisePool = async function(functions, n) {
    const doNext = async () => {
        if (!functions.length) {
            return Promise.resolve()
        }
        await functions.shift()()
        await doNext()
    }
    return Promise.all(
        new Array(n)
        .fill(0)
        .map(doNext)
    )
};

Typescript

type F = () => Promise<any>;

function promisePool(functions: F[], n: number): Promise<any> {
    const doNext = async () => {
        if (!functions.length) {
            return Promise.resolve()
        }
        await functions.shift()()
        await doNext()
    }
    return Promise.all(
        new Array(n)
        .fill(0)
        .map(doNext)
    )
};