A simple task queue class

Queue.js

function Queue() {
  this.tasks = [];
  this.results = [];
  this.onFinished = null;
}

Queue.prototype._taskComplete = function() {
  this.results.push(arguments);
  this._runNextTask();
};

Queue.prototype._runNextTask = function() {
  if (this.tasks.length === 0) {
    // No more tasks, call the callback.
    this.onFinished(this.results);
    return;
  }
  
  var task = this.tasks.shift();
  task(this._taskComplete.bind(this));
};

Queue.prototype.add = function(task) {
  this.tasks.push(task);
};

Queue.prototype.run = function(cb) {
  this.onFinished = cb;
  this.results = [];
  this._runNextTask();
};