server.js

// create server
const WebSocket = require('ws');
const { randomUUID } = require('crypto');
const PORT = 8080;

const server = new WebSocket.WebSocketServer({ port: PORT });
const activeClients = new Map();

// server got connection request -> now socket object has the specific client bounded

server.on('connection', (socket, req) => {
  console.log('coming connection request from ', req.socket.remoteAddress);
  const newId = randomUUID();
  activeClients.set(socket, newId);

  socket.isAlive = true;
  socket.on('pong', () => {
    // console.log(`client ${activeClients.get(socket)} sends pong!`);
    socket.isAlive = true;
  });
  socket.on('message', (data) => {
    console.log(`Client ${newId} sends : ${data}`);
    server.clients.forEach((client) => {
      if (client != socket && client.readyState == WebSocket.OPEN) {
        // send message to that client

        client.send(JSON.stringify({ msg: data.toString(), id: newId }));
      }
    });
  });

  socket.on('close', () => {
    console.log(`client ${activeClients.get(socket)} disconnected`);
    activeClients.delete(socket);
  });

  // on pong set isAlive to true

  socket.on('error', (err) => {
    console.log(`Error on client ${activeClients.get(socket)}: ${err}`);
  });
});

const pingInterval = setInterval(() => {
  server.clients.forEach((client) => {
    if (client.isAlive == false) {
      console.log('Terminating dead connection ', activeClients.get(client));
      activeClients.delete(client);
      return client.terminate();
    }
    client.isAlive = false;
    client.ping();
  });
}, 10000);

server.on('close', () => clearInterval(pingInterval));
console.log('Websocket started at port 8080');