Limited parallel async operations (aka Queue/Workers) in JavaScript ES6 (most compact code - essential parts only)

complete-example.js

const queueSize = 10
const parallelWorkerCount = 3

const sampleQueue = ','.repeat(queueSize).split(',').map(()=>Math.floor(Math.random()*1000))
console.log('sampleQueue:', sampleQueue)

const queueGenerator = (function *(){
    for (const item of sampleQueue) yield item;
})()

// Demonstrate how picking a work from the queue works using the queueGenerator
console.log('pick a work:', queueGenerator.next().value)
console.log('pick a work:', queueGenerator.next().value)
console.log('pick a work:', queueGenerator.next().value)

const sampleAsyncOp = (job, ms) => new Promise( (res, rej) => setTimeout(()=>res(job), ms) )

const workers = ','.repeat(parallelWorkerCount).split(',').map((v,i)=>i+1)

const allAsyncOps = []
let queueEndReached = false;

workers.forEach( async worker => {
  console.log("Worker", worker, "started!")
  for (const job of queueGenerator) {
    const jobTime = Math.random()*6000+500;
    console.log("Worker", worker, "PICKED Job", job, `(takes ${Math.floor(jobTime/100)/10}s)`)
    const asyncOp = sampleAsyncOp(job, jobTime)
    allAsyncOps.push(asyncOp)
    const jobResult = await asyncOp
    console.log("Worker", worker, "FINISHED Job", job, `(confirmed ${jobResult==job})`)
  }
  console.log("Worker", worker, "has no job!")
  if (!queueEndReached) {
    console.log("First jobless worker. End of Queue Reached! Waiting for all to finish.")
    Promise.all(allAsyncOps).then(results => console.log("ALL FINISHED!!!", results))
    queueEndReached = true;
  }
})

limited-parallel-async.js

const parallelWorkers = [....]
const jobs = [....]

const queueGenerator = (function* () {
  for (const job of jobs) yield job
})()

parallelWorkers.forEach(worker => {
  for (const nextUnpickedJob of queueGenerator) {
    await assignTask(worker, nextUnpickedJob)
  }
})