app.js

var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
app.get('/', function(req, res){
res.sendfile('index.html');
});
users = [];
io.on('connection', function(socket){
console.log('A user connected');
socket.on('setUsername', function(data){
console.log(data);
if(users.indexOf(data) > -1){
socket.emit('userExists', data + ' username is taken! Try some other username.');
}
else{
users.push(data);
socket.emit('userSet', {username: data});
}
});
socket.on('msg', function(data){
//Send message to everyone
io.sockets.emit('newmsg', data);
})
});
http.listen(3000, function(){
console.log('listening on localhost:3000');
});