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README.md

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+observer.js
+===========
+An implementation of the observer design pattern. 
+
+Tested Platforms: V8 (Node)
+
+From NPM
+========
+npm install observer
+
+Usage
+=====
+To create a pub/sub table:
+    var EventBroker = require('observer').EventBroker;
+
+    var events = new EventBroker;
+    events.create('foobar');
+
+    events.subscribe('foobar', console.log.bind(console,'observer#1:') );
+    events.subscribe('foobar', console.log.bind(console,'observer#2:') );
+
+    events.publish('foobar',3,14);
+
+    // => observer#1, 3, 14
+    // => observer#2, 3, 14
+
+To create an observable class:
+    var Observable = require('observer').Observable,
+        inherits   = require('util').inherits;
+
+    function Foobar(){
+      Observable.call(this);
+      this.create('qux');
+    }
+
+    var f = new Foobar();
+    f.on('qux', console.log.bind(console, 'observer#3:');
+    f.events.publish('qux',3,14);
+
+    // => observer#3, 3, 14
+
+Testing
+=======
+node test/test.js

lib/observer.js

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+var EventBroker = exports.EventBroker = function EventBroker(){
+  this.subjects = {};
+};
+
+EventBroker.prototype.subscribe = function(subject,callback){
+  this.get(subject).push(callback);
+};
+
+EventBroker.prototype.create = function(subject){
+  this.subjects[subject] = []; 
+};
+
+EventBroker.prototype.get = function(subject){
+  if( !this.has(subject) ) {
+    throw new Error("Subject Not Found: "+subject);
+  }
+
+  return this.subjects[subject];
+};
+
+EventBroker.prototype.has = function(subject){
+  return this.subjects.hasOwnProperty(subject);
+}
+
+EventBroker.prototype.publish = function(subject){
+  var subscribers = this.get(subject),
+      args = Array.prototype.slice.call(arguments,1);
+
+  args.splice(0,0, undefined);
+
+  for(var i = -1, len=subscribers.length; ++i < len; ){
+    setTimeout(Function.prototype.bind.apply(subscribers[i], args), 0);   
+  };
+};
+
+function Observable(){
+  this.events = new EventBroker;
+  this.on = this.events.subscribe.bind(this.events);
+};
+
+module.exports = {
+  'Observable':Observable,
+  'EventBroker':EventBroker
+};

package.json

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+{
+  "name":"observer",
+  "version":"1.0.0",
+  "description":"An implementation of observer design pattern.",
+  "author":"Azer Koculu <azer@kodfabrik.com>",
+  "keywords":["observer","pubsub","events"],
+  "directories":{ "lib": "./lib" },
+  "main":"./lib/observer"
+}

test/test.js

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+var assert = require('assert'),
+    inherits = require('util').inherits,
+    Observable = require('../lib/observer').Observable;
+
+function Cal(){
+  Observable.call(this);
+
+  this.events.create('sum');
+  this.events.create('sub');
+  this.events.create('mul');
+}
+
+inherits(Cal, Observable);
+
+Cal.prototype.sum = function(x,y){
+  this.events.publish('sum', x+y);
+};
+
+Cal.prototype.sub = function(x,y){
+  this.events.publish('sub',y-x);
+};
+
+Cal.prototype.mul = function(x,y){
+  this.events.publish('mul', x*y);
+  async = true;
+};
+
+var pi = new Cal(),
+    async = false;
+
+pi.on('sum', pi.sub.bind(pi,0.43));
+pi.on('sub', pi.mul.bind(pi,2));
+pi.on('mul', function(val){
+  assert.ok(async);
+  pi.value = val;
+});
+
+pi.sum(1.3,0.7);
+
+process.addListener('exit', function(){
+  assert.ok(pi.value, 3.14);
+});