app.js

var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);

var clients = {};

app.get('/', function(req, res){
	res.send('server is running');
});

io.on('connection', function(client){
	client.on('join', function(name){
		console.log('Join: ' + name);
		clients[client.id] = name;
		client.emit("update", "You have connected to the server.");
		client.broadcast.emit("update", name + " has joined the server.");
	});
	client.on('send', function(msg){
		console.log('Message: ' + msg);
		client.broadcast.emit("chat", clients[client.id], msg);
	});

	client.on('disconnect', function(){
		if (clients[client.id] != undefined) {
			console.log('Disconnect');
			io.emit("update", clients[client.id] + " has left the server.");
		}
		delete clients[client.id];
	});
});

http.listen(3000, function(){
	console.log('listening port 3000');
});