nodejs 中为时间添加监听，常见的有
addlistener 和 on 两种方法；
别名的意思，一样的效果；
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const listenter1 =()=>{
console.log("listenter1")
};
const listenter2 =()=>{
console.log("listenter2")
};
eventsEmitter.addListener('connection',listenter1);
eventsEmitter.on('connection',listenter2);
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如同 jq 里的 on,bind；
个人偏向用 on 来处理；
随便你喜欢用哪个；
events.EventEmitter.listenerCount
这是一个计算某个事件有多少监听的计数；一半配合
addListener
removeListener
完整的代码如下
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/**
* Created by broszhu on 2017/6/30.
*/
const events=require('events');
const eventsEmitter=new events.EventEmitter();
const listenter1 =()=>{
console.log("listenter1")
};
const listenter2 =()=>{
console.log("listenter2")
};
eventsEmitter.addListener('connection',listenter1);
eventsEmitter.on('connection',listenter2);
let eventListeners=events.EventEmitter.listenerCount(eventsEmitter,"connection");
console.log(`连接数是${eventListeners}`);
eventsEmitter.emit("connection");
eventsEmitter.removeListener('connection',listenter1);
console.log("listenter1 is remove");
eventListeners=events.EventEmitter.listenerCount(eventsEmitter,"connection");
console.log(`连接数是${eventListeners}`);
eventsEmitter.emit("connection");
console.log("end");
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输出的如下
连接数是2
listenter1
listenter2
listenter1 is remove
连接数是1
listenter2
end