app.js

var app = require('http').createServer(handler);
var url= require('url');
var fs = require('fs');
var os = require('os');
var io = require('socket.io').listen(app);
var serialport = require("serialport");
var SP = serialport.SerialPort;
var serialPort = new SP("COM4",
	{
		baudrate: 115200,
		parser: serialport.parsers.readline("\n")
	}, false);

app.listen(5000);

/* SERIAL WORK */

serialPort.open(function (error) {
  if ( error ) {
    console.log('failed to open: '+error);
  } else {
    console.log('open');
    serialPort.on('data', function(data) {
      console.log('data received: ' + data);
      io.sockets.emit('serial_update', data);
    });
    //serialPort.write("ls\n", function(err, results) {
    //  console.log('err ' + err);
    //  console.log('results ' + results);
    //});
  }
});


// Http handler function
function handler (req, res) {
    
    // Using URL to parse the requested URL
    var path = url.parse(req.url).pathname;
    
    // Managing the root route
    if (path == '/') {
        index = fs.readFile(__dirname+'/three.html', 
            function(error,data) {
                
                if (error) {
                    res.writeHead(500);
                    return res.end("Error: unable to load three.html");
                }
                
                res.writeHead(200,{'Content-Type': 'text/html'});
                res.end(data);
            });

    // Managing the route for the javascript files
    } else if( /\.(js)$/.test(path) ) {
        index = fs.readFile(__dirname+path, 
            function(error,data) {
                
                if (error) {
                    res.writeHead(500);
                    return res.end("Error: unable to load " + path);
                }
                
                res.writeHead(200,{'Content-Type': 'text/plain'});
                res.end(data);
            });
    } else {
        res.writeHead(404);
        res.end("Error: 404 - File not found.");
    }
    
}