Countdown latch for AngularJS

count-down-latch.js

(function() {
  'use strict';
      
  angular.module('countDownLatch', [])
  
  .factory('CountDownLatch', function() {
    var service = {
      createInstance: function(countDown, onComplete) {
        return {
          countDown: function() {
            --countDown;
            if (countDown <= 0) {
              onComplete();
            }
          }
        };
      }     
    };
    return service;
  });
      
}());