Chat-Related Socket | Useful Reference for Room-related Socket Stuff | Link has react stuff as well

var http = require('http').createServer().listen(3000);
var io = require('socket.io').listen(http);
io.on('connection', (socket) => {
   console.log(`Connected: ${socket.id}`);
   socket.on('disconnect', () =>
      console.log(`Disconnected: ${socket.id}`));
   socket.on('join', (room) => {
      console.log(`Socket ${socket.id} joining ${room}`);
      socket.join(room);
   });
   socket.on('chat', (data) => {
      const { message, room } = data;
      console.log(`msg: ${message}, room: ${room}`);
      io.to(room).emit('chat', message);
   });
});