A chat server built purely in NodeJS without the socket.io module. Will help you chat with your roomates on the same router.

chat-server.js

process.stdout.write('\u001B[2J\u001B[0;0f'); // Cleans up the console. 

const server = require('net').createServer(); 
let counter = 0;
let sockets = {};
//function to return the current time
let timeStamp = () => {
	let now = new Date();
	return `${now.getHours()}:${now.getMinutes()}`
};

server.on('connection', socket => { //here sockets is an EventEmitter
    socket.id = counter++;
    console.log('Client Connected');
    socket.write("Please type your name: \n"); //A welcome message

    socket.on('data', data => { 
        if (!sockets[socket.id]) { //To not echo the same message to you
            socket.write(`Welcome aboard ${data}`);
            socket.name = data.trim("\n");
            sockets[socket.id] = socket;
            return;
        }
        Object.entries(sockets).forEach(([key, cs]) => { //This will broadcast message to all the people connected to the server
            // console.log(socket.id,+key);
            if (socket.id === +key) { //The key is actually a `string number` To convert a string number into a number I used the + operator, It converted my string number to key to number
                return;
            } else {
                cs.write(`${socket.name} @ ${timeStamp()} : `); 
                cs.write(`${data}`);
            }

        })
    });

    socket.on('end', () => {
        delete sockets[socket.id];
        console.log('Client Disconnected'); //Show the nessage when a client disconnects
    });
    socket.setEncoding('utf8'); //Set the encoding to whatever you like
});

server.listen(8000, () => { //Appliation listening on port 8000
    console.log('Server bound');
})

//To run this code open a terminal in Mac/Ubuntu and type nc localhost 8000 and see the magic. You can also type the local IP and chat with people probably on the same router.