Will socket.on("disconnecting") cause excessive load or overwhelm the backend?

[Bubuioc]

Hello,i want to get the socket rooms before disconnection and i found this in the docs:

io.on("connection", (socket) => {
  socket.on("disconnecting", (reason) => {
    console.log(socket.rooms); // Set { ... }
  });
});

However, I’m concerned about scalability. If I have around 1,000 connected sockets, could this overwhelm my backend? I’m not deeply experienced with JavaScript, but I know that .on is based on EventEmitter, which throws warnings if more than 10 listeners are added.

Has anyone used this in production? If so, how did it perform?

Thanks!

[darrachequesne]

Hi!

I'd say it depends on what you do in the "disconnecting" event handler. For example, notifying the other users that the user has left the chat can become a problem, if you have a spike of connections/disconnections (which can be solved by adding a disconnection grace delay, for example).