socket emit to specific room using nodejs

// sending to sender-client only
socket.emit('message', "this is a test");

// sending to all clients, include sender
io.emit('message', "this is a test");

// sending to all clients except sender
socket.broadcast.emit('message', "this is a test");

// sending to all clients in 'game' room(channel) except sender'game').emit('message', 'nice game');

// sending to all clients in 'game' room(channel), include sender'game').emit('message', 'cool game');

// sending to sender client, only if they are in 'game' room(channel)'game').emit('message', 'enjoy the game');

// sending to all clients in namespace 'myNamespace', include sender
io.of('myNamespace').emit('message', 'gg');

// sending to individual socketid'message', 'for your eyes only');

// list socketid
for (var socketid in io.sockets.sockets) {}
Object.keys(io.sockets.sockets).forEach((socketid) => {});io.on('connection', function(socket){'some room').emit('some event');});io.on('connection', socket => {  socket.on('say to someone', (id, msg) => {'my message', msg);  });});'room1').to('room2').to('room3').emit('some event');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 === {}  });});io.on('connect', onConnect);function onConnect(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'game').emit('nice game', "let's play a game");  // sending to all clients in 'game1' and/or in 'game2' room, except sender'game1').to('game2').emit('nice game', "let's play a game (too)");  // sending to all clients in 'game' room, including sender'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)'hey', 'I just met you');  // WARNING: `` will NOT work, as it will send to everyone in the room  // named `` but the sender. Please use the classic `socket.emit()` instead.  // sending with acknowledgement  socket.emit('question', 'do you think so?', function (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?');  // specifying whether the data to send has binary data  socket.binary(false).emit('what', 'I have no binaries!');  // 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');};

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