how can I use nodejs proxy behind another proxy that need authentication?

Question

I have found this code to create nodejs http proxy, but I want to use this code behind another http proxy that connect me to the Internet and need authentication (something like this http://username:password@IP:Port).

Anyproxy is another alternative and best choice for me, but I don't know how to use it behind my organization proxy. How can I make proxy chains like this:

client --> nodejs Proxy (mycode) --> organization proxy --> Internet.

//  Install npm dependencies first
//  npm init
//  npm install --save url@0.10.3
//  npm install --save http-proxy@1.11.1

var httpProxy = require("http-proxy");
var http = require("http");
var url = require("url");
var net = require('net');

var server = http.createServer(function (req, res) {
  var urlObj = url.parse(req.url);
  var target = urlObj.protocol + "//" + urlObj.host;

  console.log("Proxy HTTP request for:", target);

  var proxy = httpProxy.createProxyServer({});
  proxy.on("error", function (err, req, res) {
    console.log("proxy error", err);
    res.end();
  });

  proxy.web(req, res, {target: target});
}).listen(8080);  //this is the port your clients will connect to

var regex_hostport = /^([^:]+)(:([0-9]+))?$/;

var getHostPortFromString = function (hostString, defaultPort) {
  var host = hostString;
  var port = defaultPort;

  var result = regex_hostport.exec(hostString);
  if (result != null) {
    host = result[1];
      if (result[2] != null) {
        port = result[3];
      }
  }

  return ( [host, port] );
};

server.addListener('connect', function (req, socket, bodyhead) {
  var hostPort = getHostPortFromString(req.url, 443);
  var hostDomain = hostPort[0];
  var port = parseInt(hostPort[1]);
  console.log("Proxying HTTPS request for:", hostDomain, port);

  var proxySocket = new net.Socket();
  proxySocket.connect(port, hostDomain, function () {
    proxySocket.write(bodyhead);
    socket.write("HTTP/" + req.httpVersion + " 200 Connection established\r\n\r\n");
  }
  );

  proxySocket.on('data', function (chunk) {
    socket.write(chunk);
  });

  proxySocket.on('end', function () {
    socket.end();
  });

  proxySocket.on('error', function () {
    socket.write("HTTP/" + req.httpVersion + " 500 Connection error\r\n\r\n");
    socket.end();
  });

  socket.on('data', function (chunk) {
    proxySocket.write(chunk);
  });

  socket.on('end', function () {
    proxySocket.end();
  });

  socket.on('error', function () {
    proxySocket.end();
  });

});