timer.js

var counter = { x: 0 };
var p = [];

function count(c) {
  var time = Math.floor(Math.random() * 1000);
  return new Promise(function (resolve) {
    setTimeout(function () {
      var x = c.x++;
      console.log(x + ':' + time);
      resolve(x + ':' + time);
    }, time);
  });
}


for (var i = 0; i < 1000; i++) {
  p.push(count(counter));
}

Promise.all(p).then(console.log.bind(console));
4,000,000