io.emit vs socket.emit vs socket.broadcast.emit

Send message to one client, like New user come, we show him "welcome message" 

socket.emit('message', "Welcome user to our Chat Group");

Sending to all clients except sender 

socket.broadcast.emit('message', "New user i.e joy joined our chat group."); 

Sending to all clients in 'game' room(channel) except sender

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

Sending to sender client, only if they are in 'game' room(channel)

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

Sending to individual socketid

socket.broadcast.to(socketid).emit('message', 'sending to individual socketid'); 

Sending to all clients, include sender

io.emit('message', "sending to all clients, include sender"); 

Sending to all clients in 'game' room(channel), include sender

io.in('game').emit('message', 'sending to all clients in game room'); 

sending to all clients in namespace 'myNamespace', include sender

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

for emiting to specific clients

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

send to all connected clients 

io.sockets.emit('send to all connected clients');