app.js

var express = require('express'),
	app = express(),
	server = require('http').createServer(app),
	io = require('socket.io').listen(server),
	users = {};

server.listen(3000,'0.0.0.0');

app.get('/', function(req, res){
	res.sendFile(__dirname + '/index.html');
});

io.sockets.on('connection', function(socket){
	socket.on('new user', function(data, callback){
		if (data in users){
			callback(false);
		} else{
			callback(true);
			socket.nickname = data;
			users[socket.nickname] = socket;
			updateNicknames();
		}
	});

	function updateNicknames(){
		io.sockets.emit('usernames', Object.keys(users));
        //console.log(users);
	}

	socket.on('send message', function(data, callback){
		var msg = data.trim();
		console.log('after trimming message is: ' + msg);
		if(msg.substr(0,3) === '/w '){
			msg = msg.substr(3);
			var ind = msg.indexOf(' ');
			if(ind !== -1){
				var name = msg.substring(0, ind);
				var msg = msg.substring(ind + 1);
				if(name in users){
					users[name].emit('whisper', {msg: msg, nick: socket.nickname});
					console.log('message sent is: ' + msg);
					console.log('Whisper!');
				} else{
					callback('Error!  Enter a valid user.');
				}
			} else{
				callback('Error!  Please enter a message for your whisper.');
			}
		} else{
			io.sockets.emit('new message', {msg: msg, nick: socket.nickname});
		}
	});

    socket.on('typing', function(data){
        data = socket.nickname+": "+data;
        io.sockets.emit('live-type', data);
    });

	socket.on('disconnect', function(data){
		if(!socket.nickname) return;
		delete users[socket.nickname];
		updateNicknames();
	});
});
//console.log(users);