javascript publish/subscribe or observer pattern

 定义

定义一对多的对象封装，目标对象状态发生变化，它全部的接受者都会收到通知并作相应的更新。

使用频率：5/5 最高

概要

观察者模式，也就是发布者/订阅者模式，当发布者发布一个通知的时候，订阅者就会收到通知，并调用本身的更新方法，作些什么事情。这种通知是单向的，只能由发布者向订阅者发布通知。

图标说明

示例代码

      var Publisher = function () {        this.subscribers = [];      }      Publisher.prototype = {          constructor: Publisher,          addSubscriber: function(subscriber){            this.subscribers.push(subscriber);          },          removeSubscriber: function(subscriber){            var subscribers = this.subscribers,              len = subscribers.length,              i = 0;            for(; i < len; i++){              if (subscribers[i] === subscriber) {                delete subscribers[i];                break;              };            }          },          notifySubscriber: function(message){            var subscribers = this.subscribers,              len = subscribers.length,              i = 0;            for(; i< len; i++){              subscribers[i].receiveMessage(message);            }          }      };      var Subscriber = function(subscriberName, publisher){        this.name = subscriberName;        this.publisher = publisher;      };      Subscriber.prototype = {        constructor: Subscriber,        receiveMessage: function(message){          console.log('I am ' + this.name + ' I receive: ' + message);        }      };      var publisher = new Publisher();      var subUser_001 = new Subscriber('subUser_001', publisher);      var subUser_002 = new Subscriber('subUser_002', publisher);      var subUser_003 = new Subscriber('subUser_003', publisher);      publisher.addSubscriber(subUser_001);      publisher.addSubscriber(subUser_002);      publisher.addSubscriber(subUser_003);      publisher.notifySubscriber('百度推送新闻了');