A very simple TCP chat server written in Node.js

SimpleChatServer.js

//ooen all required modules
var net = require('net');
var util = require('util');

//declare the sockets array and port number
var sockets = [];
var port = 4000;
 
//start the chat server
require('net').createServer(function(socket){
	
	//give the socket a unique handle
	socket.name = socket.remoreAddress + ':' + socket.remotePort;
		
	//add the new socket to the socket array
	sockets.push(socket);
	
	//welcome message and inform other registered sockets
	//that a new socket has joined the chat
	socket.write('Welcome ' + socket.name + ' to the chat service\n');
	broadcastMessage(socket.name + ' has joined the chat service\n', socket);
	
	//broadcast the message to all registered clients
	socket.on('data', function(data){
		broadcastMessage(data, socket);
	});
 
	//inform other registered clients when a socket leaves the chat
	socket.on('end', function(){
		var pos = sockets.indexOf(socket);
		if (pos > 0){
			broadcast(socket.name + ' has left the chat service\n');
			sockets.splice(pos, 1);
		}
	});
	
	//Broadcast message to all registered sockets
  	function broadcastMessage(message, sender) {
    	sockets.forEach(function (client) {
		if (client === sender) {
      		return;
      	}
      	if (message && message.length > 0){
      		client.write(message);
      	}
    });
    // write the message to standard output too
    process.stdout.write(message);
  }
}).listen(port);
 
console.log('Chat server listening on port ' + port);