Node.js中許多對(duì)象都會(huì)觸發(fā)事件：當(dāng)一個(gè)文件被打工的時(shí)候fs.ReadStream被觸發(fā)岖食，當(dāng)一個(gè)用戶連接被建立的時(shí)候net.Server中的事件被觸發(fā)，所有的對(duì)象的事件相關(guān)的方法繼承自EventEmitter,可以通過(guò)require("events")來(lái)加載事件模塊嫌吠。
var EventEmitter = require('events');
如何讓一個(gè)對(duì)象俱備事件相關(guān)的方法匾竿？
'use strict';
const util = require('util');
const EventEmitter = require('events');
function MyEventEmitter() {
// Initialize necessary properties from `EventEmitter` in this instance
EventEmitter.call(this);
}
// Inherit functions from `EventEmitter`'s prototype
util.inherits(MyEventEmitter, EventEmitter);
EventEmitter.defaultMaxListeners 默認(rèn)最大監(jiān)聽(tīng)數(shù)量
Event: 'removeListener' 當(dāng)某監(jiān)聽(tīng)者移除事件時(shí)觸發(fā)
emitter.addListener(event, listener) 是emitter.on的別名
Event: 'newListener'增加事件監(jiān)聽(tīng)者的時(shí)候觸發(fā)
server.on('connection', function (stream) {
console.log('someone connected!');
});
console.log(util.inspect(server.listeners('connection'))); // [ [Function] ]
emitter.once(event, listener)
server.once('connection', function (stream) {
console.log('Ah, we have our first user!');
});
