Observer Pattern

gistfile1.js

// http://shichuan.github.com/javascript-patterns/

var observer = {
     addSubscriber : function(callback){
          this.subscribers[this.subscribers.length] = callback;
     },
     removeSubscriber : function(callback){
          for(var i = 0; i < this.subscribers.length; i++){
               if(this.subscribers[i] === callback){
                    delete this.subscribers[i];
               };
          };
     },
     publish : function(){
          for(var i = 0; i < this.subscribers.length; i++){
               if(typeof this.subscribers[i] === 'function'){
                    this.subscribers[i](what);
               };
          };
     },
     make : function(o){
          for(var i in this){
               if(this.hasOwnProperty(i)){
                    o[i] = this[i];
                    o.subscribers = [];
               };
          };
     }
};

var blogger = {
     writeBlogPost : function(){
          var content = 'Today is ' + new Date();
     }
};

var la_times = {
     newIssue : function(){
          var paper = 'Matians have landed on Earth!';
     }
};

observer.make(blogger);
observer.make(la_times);

var jack = {
     read : function(what){
          console.log('I just read that ' + what);
     }
};

var jill = {
     gossip : function(what){
          console.log('You didn\'t hear it from me, but ' + what);
     }
};

blogger.addSubscriber(jack.read);
blogger.addSubscriber(jill.gossip);
blogger.writeBlogPost();

blogger.removeSubscriber(jill.gossip);
blogger.writeBlogPost();

la_times.addSubscriber(jack.read);
la_times.addSubscriber(jill.gossip);
la_times.newIssue();