Node.js中的事件

var util = require("util"); //导入util模块
var events = require("events"); //导入events模块
module.exports = MyStream;

function MyStream() {
    events.EventEmitter.call(this); //call方法使得MyStream对象继承了EventEmitter对象上的方法
}
util.inherits(MyStream, events.EventEmitter);   //使用inherits方法

MyStream.prototype.write = function (data) {    //MyStream对象扩展了一个write方法，它可以使用emit触发事件
    this.emit("data", data);
};

var stream = new MyStream();    //构建一个stream对象

console.log("stream instanceof events.EventEmitter: " + (stream instanceof events.EventEmitter)); //判断stream对象是不是EventEmitter对象的实例，这里为true
console.log("MyStream.super_ === events.EventEmitter: " + (MyStream.super_ === events.EventEmitter)); //MyStream的父类是不是EventEmitter，这里为true

stream.on("data", function (data) {
    console.log(‘Received data: "‘ + data + ‘"‘);
});
stream.write("It works1!");
stream.write("It works2!");