event-loop-play.js

console.log('experiment')

var intervalTime = 1000;
setInterval(runSomething, intervalTime);

var lastTime = Date.now();;
function runSomething() {
  var now = Date.now();
  var elapsed = now - lastTime;
  lastTime = now;
  var lag = elapsed - intervalTime;
  console.log('Running something. Lag:', lag);
}


var count = 2000;
var limit = 50;
var scheduled, done;
proceed();
function proceed() {
  scheduled = 0;
  done = 0;
  while (count --> 0 && ++scheduled <= limit)
    setTimeout(somethingElse(count), 500);
}

function somethingElse(count) {
  return function() {
    if (count % 100 === 0)
      console.log(2000 - count);

    var start = Date.now();
    while (Date.now() - start < 4);

    done++;
    if (done === limit)
      proceed();
  }
}