javascript - 将对象作为参数发送到回调函数-nodejs

Question

我正在为某个项目实现一个http 服务器。

我创建了一个 HttpServer 对象，其中包含一个服务器(网络模块)

该服务器包含分配的信息，我想将其作为参数传递给回调函数。就像您对“setTimeout”所做的那样

var time=setTimeout(function(**a**){do somthing}, 2000, **someObject**);

我尝试在代码中执行类似的操作，但它无法识别我作为对象传递的参数

var net = require('net');

function HttpServer(port){
    this.port=port;
}

HttpServer.prototype.start = function (){
    console.log("starting the server");
    this.server = net.createServer(function (socket,server) {
        console.log("my port is: "+server.port)
        socket.on('data',function(dat){  });
                                                 },this);
        //i am trying to send to the createserver callback function
        //the parameter 'this' that actually is an HttpServer
        //and  the callback function secives it as 'server' 
        //when i run the program i get an error that server is
        //undefiend and therefor does not have a member port

    this.server.listen(this.port);
}

var httpserver= new HttpServer(4444);
httpserver.start();

为什么无法识别发送的参数？

Answer 1

var net = require('net');

function HttpServer(port){
    this.port=port;
}

HttpServer.prototype.start = function (){
    console.log("starting the server");
    var that = this;    //Store this to that variable
    this.server = net.createServer(function (socket, server) {
        console.log('Server port is: ' + that.port); // Use that in an anonymous function
        socket.on('data',function(dat){  });
    });
    this.server.listen(this.port);

}


var httpserver= new HttpServer(4444);
httpserver.start();