io.sockets.sockets deprecated - get all sockets in v3.

It seems that io.sockets.sockets is deprecated in v3 and following does not work anymore:

socket.userId = id;

// Later
for (let s in io.sockets.sockets) {
	let socket = io.sockets.sockets[s];
	if (socket.userId === ...) {
		socket.emit(f, ...params);
	}
}

Tried also following (https://socket.io/docs/server-api/#namespace-clients-callback)…

io.clients((error, clients) => {
	if (error) throw error;
	console.log(clients);
});

But:

Uncaught TypeError: io.clients is not a function

Also io.engine.clients does not seem to expose client’s socket object, so if that’s the only way, I’d need to make custom client-id to userId table and try to keep it in sync, which feels bad idea. And if it really is, how it should be used exactly?

socket.on('v3test', function() {
	console.log(socket.id);
	for (let s in io.engine.clients) {
		let socket2 = io.engine.clients[s];
		console.log(socket2.id);
	}
});

In localhost with 1 client you’d expect 2 identical ids, but:

a9C3bHfHsfoA1aPJAAAB
FrOECbewjLGBnAzFAAAA

Please advice how to go through all connected clients in v3?

(and to clarify, the room approach is not viable in this case as the exact recipients are checked case-by-case)

[darrachequesne]

It is allowed to make io.on('connection', (socket) => { an async function?

Yes, totally 👍

[oshihirii]

I’m having to do a major refactor on multiple package implementations after a hiatus from a project.

I used to have:

io.clients((error, clients) => {
    if (error) throw error;
    console.log("io.clients list is currently:");
    console.log(clients);
    // this returns an array of socket id strings eg:
    // [6em3d4TJP8Et9EMNAAAA, G5p55dHhGgUnLUctAAAB]
});

within:

io.on('connection', (socket) => {
//...
}); 

In order to use await (per the examples here):

const ids = await io.allSockets();
console.log("io.allSockets() is currently:");
console.log(ids); 

The containing function needs to be async.

It is allowed to make io.on('connection', (socket) => { an async function?