// List of socket.io functions

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

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

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

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

socket.broadcast.to(socketid).emit('message', 'for your eyes only'); //sending to individual socketid

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

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

socket.emit(); //send to all connected clients

socket.broadcast.emit(); //send to all connected clients except the one that sent the message

socket.on(); //event listener, can be called on client to execute on server

io.sockets.socket(); //for emiting to specific clients

io.sockets.emit(); //send to all connected clients (same as socket.emit)

io.sockets.on() ; //initial connection from a client.

io.to('room').emit('a new user has joined the room'); // broadcast to everyone in the room