Pure WebSocket Node.js Server using Native HTTP Module

websocket-client.js

// make a request
const options = {
    port: 1337,
    host: 'localhost',
    headers: {
        'Connection': 'Upgrade',
        'Upgrade': 'websocket'
    }
};
const protocol = 'http'
// if your protocol is https you will need to require https module instead of http
const http = require(protocol)
const req = http.request(options);
req.end();

req.on('upgrade', (res, socket, upgradeHead) => {
    console.log('got upgraded!');
    socket.on('data', data => {
        console.log('client received', data.toString())
    })
    
    // keep sending messages
    setInterval(() => {
        socket.write('Hello!')
    }, 500)
    
});

websocket-server.js

const http = require('http');
const port = 1337


// when curl http:localhost://1337
const server = http.createServer((req, res) => {
    res.writeHead(200, { 'Content-Type': 'text/plain' });
    res.end('hey there');
});

server.on('upgrade', (req, socket, head) => {
    const id = Date.now()
    const headers = [
        'HTTP/1.1 101 Web Socket Protocol Handshake',
        'Upgrade: WebSocket',
        'Connection: Upgrade',
        ''
    ].map(line => line.concat('\r\n')).join('')

    socket.write(headers);
 
    socket.on('data', data => {
        console.log('server!', data.toString());
        socket.write(`replying ${data.toString()} ${new Date().toISOString()}`)
    });

    socket.on('end', _ => { console.log(`${id} disconnected!`) })

});

// Now that server is running
server.listen(port, () => console.log('server runnig at', port));

Thanks!