A Simple TCP Chat Server In Node Js

server.js

//run this with 'node server.js' and then test in multiple computers using 'telnet 192.168.0.1 9000'
// replace '192.168.0.1' with your ip.
(function () {
    'use strict';
    let net = require('net');
    let chatServer = net.createServer(),
        clientList = []; // a list of connected clients/ machines

    chatServer.on('connection', function (client) {
        //once a client connects we add it to our clientList
        clientList.push(client);
        client.write('Connected \r\n');
        let message = ""; //holds chunks of the message being typed by a client until the user presses 'enter'
        client.on('data', function (data) {
            // since tcp sends every character in its own request we have to store every character typed in the message variable
            message += data;
            clientList.forEach(function (clientConnected) {
                //display message to all connected clients except the current client typing. We do this to avoid double display
                //of the typed message to the current client typing;
                if (clientConnected !== client) {
                    // only sending data when the 'enter' key is pressed. '0d0a' is the hexadecimal representation of 'enter' key
                    if (data.toString('hex') === '0d0a') {
                        clientConnected.write(message);
                        // after sending the message reset it back to blank.
                        message = "";
                    }
                }
            });
        });
        // when a client leaves the chat we have to remove it from our list to avoid sending messages to unexisting client
        //which raises errors
        client.on('end',function(){
            clientList.splice(clientList.indexOf(client),1);
        });
    });
    chatServer.listen(9000);
}());