Throttiling async calls

AsyncCallsThrottling.js

class TicketProvider{
    constructor(maxActiveTickets){
        this.activeTickets = 0;
        this.maxActiveTickets = maxActiveTickets;
        this.waitingTickets = []; //array of resolve function, to get invoked once we have a free slot, so the code waiting for the ticket can move on
    }

    //returns Promise<void>
    getTicket(){
        if (this.activeTickets<this.maxActiveTickets){
            this.activeTickets++;
            return Promise.resolve();
        }
        else {
            return new Promise(res => {
                //save the resolve function so that we can invoke it when another ticket gets released
				this.waitingTickets.push(res);
            });
        }
    }

    releaseTicket(){
        this.activeTickets--;
        let nextTicketToResolve = this.waitingTickets.shift();
        if (nextTicketToResolve) {
            nextTicketToResolve();
        }
    }
}

function getRandomInt(max) {
    return Math.floor(Math.random() * Math.floor(max));
  }

  //returns Promise<string>
function getPost(postId){
    console.log("getPost " + postId + " started");
    return new Promise(res => {
        setTimeout(() => {
            console.log("---> getPost " + postId + " finishing");
            res(`${postId} - content`)
        }, 2000 * (1 + getRandomInt(2)));
    });
}

//returns :Promise<string>
async function getPostAndReleaseTicket(postId, ticketProvider){
    let post = await getPost(postId);
    ticketProvider.releaseTicket();
    return post;
}

//returns :Promise<string>
async function getTicketAndGetPostAndReleaseTicket(postId, ticketProvider){
    await ticketProvider.getTicket();
    let post = await getPost(postId);
    ticketProvider.releaseTicket();
    return post;
}

async function runWithoutThrottling(){
    let curPos = 0;
    let requests = [];
    while (curPos < 10){
        requests.push(getPost(curPos));
        curPos++;
    }
    await Promise.all(requests);
    console.log("all posts retrieved");
}

async function runWithThrottling1(){
    let ticketProvider = new TicketProvider(3);
    let curPos = 0;
    let requests = [];
    while (curPos < 10){
        let ticket = await ticketProvider.getTicket();
        requests.push(getPostAndReleaseTicket(curPos, ticketProvider));
        curPos++;
    }
    await Promise.all(requests);
    console.log("all posts retrieved");
}

async function runWithThrottling2(){
    let ticketProvider = new TicketProvider(3);
    let curPos = 0;
    let requests = [];
    while (curPos < 10){
        requests.push(getTicketAndGetPostAndReleaseTicket(curPos, ticketProvider));
        curPos++;
    }
    await Promise.all(requests);
    console.log("all posts retrieved");
}

let op = process.argv.length > 2 ? process.argv[2] : "1"; 

switch (op){
    case "0":
        runWithoutThrottling();
        break;

    case "1":
        runWithThrottling1();
        break;

    case "2":
        runWithThrottling2();
        break;
}