ng-pubsub-service.js

(function(){
'use strict';

function PubSubService(){
  /**
   * based on: http://davidwalsh.name/pubsub-javascript
   */
  var topics = {};

  //----------------------------------------------------------------------------
  //--- @begin: internal logic

  function checkProperty(topic){
    return (topics.hasOwnProperty.call(topics, topic));
  }
  
  function subscribers(topic){
    if(!checkProperty(topic)){
      return [];
    } else {
      return topics[topic];
    }
  }

  function findIndexOf(topic, listener){
    if(!checkProperty(topic)){
      return -1;
    } else {
      return topics[topic].indexOf(listener);
    }
  }

  function unsubscribe(topic, listener){
    var index = findIndexOf(topic, listener);
    if(index > -1){
      topics[topic].splice(index, 1);
    }
    index = null;
  }

  function subscribe(topic, listener){
      // Create the topic's object if not yet created
      if(!checkProperty(topic)){
        topics[topic] = [];
      }

      if(findIndexOf(topic, listener) > -1){
        // listener already registered
        return;
      }

      // Add the listener to queue
      topics[topic].push(listener);

      listener.unsubscribe = function internalUnsubscribe(){
        unsubscribe(topic, listener);
        topic = null;
        listener = null;
      };

      return {
        unsubscribe : listener.unsubscribe
      };
  }

  function publish(topic, data){
    // If the topic doesn't exist, or there's no listeners in queue, just leave
    if(!checkProperty(topic)){
      return;
    }

    // Cycle through topics queue, fire!
    topics[topic].forEach(function(item) {
      item(data);
    });
  }

  //--- @end: internal logic
  //----------------------------------------------------------------------------

  //--- API
  return {
    subscribers : subscribers,
    subscribe : subscribe,
    unsubscribe : unsubscribe,
    publish : publish
  };
}

// PubSubService.$inject = [];

angular
  .module('app')
  .factory('PubSubService', PubSubService);

})();