Pub/Sub

pubsub.js

var PubSub = {
  subscribe: function(ev, callback) {
    var calls = this._callbacks || (this._callbacks = {});
    (this._callbacks[ev] || (this._callbacks[ev] = [])).push(callback);
    
    return this;
  },
  
  publish: function() {
    var args = Array.prototype.slice.call(arguments, 0);
    
    var ev = args.shift();
    
    var list, calls, i, l;
    
    if (!(calls = this._callbacks)) return this;
    if (!(list = this._callbacks[ev])) return this;
    
    for (i = 0, l = list.length; i < l; i++) 
      list[i].apply(this, args);
      
    return this;
  }
};

PubSub.subscribe("wem", function() {
  alert("wem");
});

PubSub.publish("wem");

// from JavaScript Web Applications by MacCaw
// jQuery 版 https://gist.github.com/isao/799721