nodejs事件

var events=require('events');
var eventEmitter=new events.EventEmitter();
//创建事件处理程序
var connectHandler=function connected(){
console.log('connect success');
eventEmitter.emit('data_received');
};

eventEmitter.on('connection',connectHandler);
//使用匿名函数绑定data_received
eventEmitter.on('data_received',function(){
console.log('data received success');
});
eventEmitter.emit('connection');//触发事件connection
console.log('end');

//观察者模式
//一个事件可以有多个监听者，事件的发生不用关心谁来处理，便于解耦。