emit cheatsheet

io.on("connection", (socket) => {

  // sending to the client
  socket.emit("hello", "can you hear me?", 1, 2, "abc");

  // sending to all clients except sender
  socket.broadcast.emit("broadcast", "hello friends!");

  // sending to all clients in "game" room except sender
  socket.to("game").emit("nice game", "let's play a game");

  // sending to all clients in "game1" and/or in "game2" room, except sender
  socket.to("game1").to("game2").emit("nice game", "let's play a game (too)");

  // sending to all clients in "game" room, including sender
  io.in("game").emit("big-announcement", "the game will start soon");

  // sending to all clients in namespace "myNamespace", including sender
  io.of("myNamespace").emit("bigger-announcement", "the tournament will start soon");

  // sending to a specific room in a specific namespace, including sender
  io.of("myNamespace").to("room").emit("event", "message");

  // sending to individual socketid (private message)
  io.to(socketId).emit("hey", "I just met you");

  // WARNING: `socket.to(socket.id).emit()` will NOT work, as it will send to everyone in the room
  // named `socket.id` but the sender. Please use the classic `socket.emit()` instead.

  // sending with acknowledgement
  socket.emit("question", "do you think so?", (answer) => {});

  // sending without compression
  socket.compress(false).emit("uncompressed", "that's rough");

  // sending a message that might be dropped if the client is not ready to receive messages
  socket.volatile.emit("maybe", "do you really need it?");

  // sending to all clients on this node (when using multiple nodes)
  io.local.emit("hi", "my lovely babies");

  // sending to all connected clients
  io.emit("an event sent to all connected clients");

});io.on('connection', socket => {  socket.on('disconnecting', () => {    const rooms = Object.keys(socket.rooms);    // the rooms array contains at least the socket ID  });  socket.on('disconnect', () => {    // socket.rooms === {}  });});