socket server with express

app.js

const Server = require('socket.io');
const app = express();
const server = http.createServer(app);
const io = new Server(server);

io.on('connection', (socket) => {
  console.log(`Connection detected: ${socket.client.id}`);
  socket.use(([name, data], next) => {
    if (data.auth === process.env.SOCKET_KEY) {
      return next();
    }
    console.log(`Auth failure detected: ${socket.client.id}`);
    socket.disconnect();
    return false;
  });
  socket.on('event', (event) => {
    socketEvents.eventHandler(socket, event);
  });
  socket.on('action', (action) => {
    socketEvents.actionHandler(socket, action);
  });
});

index.js

const server = require('./server/app');
const PORT = process.env.PORT || 8080;

server.listen(PORT, () => {
  console.log(art);
  console.log(`SERVER LISTENING: ${PORT}`);
});

socketHandler.js

const eventHandler = (socket, event) => {
  socket.emit('event:ack', event);
};

const actionHandler = (socket, action) => {
  const { type, payload } = action;

  switch (type) {
    case SERVER_HELLO:
      console.log('Got hello payload!', payload);
      socket.emit('action', { type: 'MESSAGE', payload: 'good day!' });
      break;
    case SERVER_TEST_PASSED:
      const grader = new Grader(payload.userId, payload.fullName, payload.projectName);
      console.log(`SOCKET ACTION HANDLER: TESTS PASSED ==> ${payload.userId}, ${payload.fullName}, ${payload.projectName}`);
      grader
        .grade()
        .then(results => socket.emit('action', { type: 'MESSAGE', payload: `statement posted, statementId: ${results}` }))
        .catch(err => socket.emit('action', { type: 'MESSAGE', payload: `statement posting error: ${err}` }));
      break;
    default:
      break;
  }
};