index.js

var express = require('express');
var app = express();
var http = require('http').Server(app);
var io = require('socket.io')(http);
var port = process.env.PORT || 4141;
var path = require('path');
 
app.get('/', function(req, res){
    res.sendFile(__dirname + '/index.html');
});
 
app.use(express.static(path.join(__dirname + '/public')));
 
 
io.on('connection', function(socket) {
 
    socket.on('user_join', function(data) {
        this.username = data;
        socket.broadcast.emit('user_join', data);
    });
 
    socket.on('chat_message', function(data) {
        data.username = this.username;
        socket.broadcast.emit('chat_message', data);
    });
 
    socket.on('disconnect', function(data) {
        socket.broadcast.emit('user_leave', this.username);
    });
});
 
http.listen(port, function() {
    console.log('Listening on *:' + port);
});