queue

gistfile1.txt

ZQueue = function() {
  this.queue = [];
  this.queued = false;
};

ZQueue.prototype.dequeue = function() {
  this.queued = false;
  this.shiftQueue();
};

ZQueue.prototype.enqueue = function(fn_to_execute) {
  // no items in queue
  if(!this.queued) {
    this.queued = true;
    fn_to_execute();
  } else {
    // queue item to run later
    this.queue.push(fn_to_execute);
  }
};

ZQueue.prototype.shiftQueue = function() {
  if(this.queue.length) {
    this.queued = true;
    var fn_to_execute = this.queue.shift();
    fn_to_execute();
  }
};

ZQueue.prototype.flushQueue = function() {
  var len = this.queue.length;
  while(len--) {
    this.dequeue();
  }
};

for loop without queue:

    var count = 0; for(var i=0; i<100; i++) { setTimeout(function() { console.log(count++); }, 10 )  }

for loop with queue:

   var que = new ZQueue();
   var count = 0; for(var i=0; i<100; i++) { que.enqueue(function() { setTimeout(function() { console.log(count++); que.dequeue(); }, 10 ) }); }