mapLimit.js

const mapLimit = async (arr, perChunk) => {
  const promiseArr = arr.reduce((all,one,i) => {
    const ch = Math.floor(i/perChunk); 
    all[ch] = [].concat((all[ch]||[]),one); 
    return all
  }, [])

  for (const promise of promiseArr) {
    await Promise.all(promise.map(func => func()))
    console.log('done!');
  }
  return 'Success!!'
}

const promiseArr = [request, request, request, request, request, request, request, request, request, request, request, request]

(async () => {
  try {
    const limit = 3;
    await mapLimit(promiseArr, limit);
  } catch (err) {
      console.log(err)
  }
})();

// or …
// ;(() => {
//   mapLimit(datadad, 3).then(console.log).catch(console.error)
// })()