socket.io/examples/nwjs-example/server/index.js

import { Server } from 'socket.io';

const io = new Server();

io.on('connection', (socket) => {
  console.log(`connect: ${socket.id}`);

  socket.on("hello", (val) => {
    console.log(val);
  });

  socket.on('disconnect', () => {
    console.log(`disconnect: ${socket.id}`);
  });
});

io.listen(3000);