This is my first snippet about SocketIO. I just wanna share this useful cheatsheet from socket.io documentation here.
// ----------- Server side
io.on("connection", (socket) => {
// basic emit back to sender
socket.emit(/* ... */);
// to all clients in the current namespace except the sender
socket.broadcast.emit(/* ... */);
// to all clients in room1 except the sender
socket.to("room1").emit(/* ... */);
// to all clients in room1 and/or room2 except the sender
socket.to(["room1", "room2"]).emit(/* ... */);
// to all clients in room1
io.in("room1").emit(/* ... */);
// to all clients in room1 and/or room2 except those in room3
io.to(["room1", "room2"]).except("room3").emit(/* ... */);
// to all clients in namespace "myNamespace"
io.of("myNamespace").emit(/* ... */);
// to all clients in room1 in namespace "myNamespace"
io.of("myNamespace").to("room1").emit(/* ... */);
// to individual socketid (private message)
io.to(socketId).emit(/* ... */);
// to all clients on this node (when using multiple nodes)
io.local.emit(/* ... */);
// to all connected clients
io.emit(/* ... */);
// to all clients, with one acknowledgement per client
io.timeout(5000).emit("hello", "world", (err, responses) => {
if (err) {
// some clients did not acknowledge the event in the given delay
} else {
console.log(responses); // one response per client
}
});
// 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.
// with acknowledgement
socket.emit("question", (answer) => {
// ...
});
// without compression
socket.compress(false).emit(/* ... */);
// a message that might be dropped if the low-level transport is not writable
socket.volatile.emit(/* ... */);
// with timeout
socket.timeout(5000).emit("my-event", (err) => {
if (err) {
// the other side did not acknowledge the event in the given delay
}
});
});
// ----------- Client side
// basic emit
socket.emit(/* ... */);
// with acknowledgement
socket.emit("question", (answer) => {
// ...
});
// without compression
socket.compress(false).emit(/* ... */);
// a message that might be dropped if the low-level transport is not writable
socket.volatile.emit(/* ... */);
// with timeout
socket.timeout(5000).emit("my-event", (err) => {
if (err) {
// the other side did not acknowledge the event in the given delay
}
});