How to store client associated data in socket.io 1.0

Question

The docs say socket.io doesn't support .get .set now

Is it okay to store client associated data like

io.sockets.on('connection', function (client) {
    client.on('data', function (somedata) {            
        client['data'] = somedata;
    });    
});

in case I need multiple nodes?

Answer 1

Yes, it is OK to add properties to the socket.io socket object. You should be careful to not use names that could conflict with built-in properties or methods (I'd suggest adding a leading underscore or namescoping them with some sort of name prefix). But a socket is just a Javascript object and you're free to add properties like this to it as long as you don't cause any conflict with existing properties.

There are other ways to do this that use the socket.id as a key into your own data structure.

var currentConnections = {};
io.sockets.on('connection', function (client) {
    currentConnections[client.id] = {socket: client};
    client.on('data', function (somedata) {  
        currentConnections[client.id].data = someData; 
    });    
    client.on('disconnect', function() {
        delete currentConnections[client.id];
    });
});

Answer 2

Yes, that's possible as long as there is no other builtin properties with same name.

io.sockets.on('connection', function (client) {
    client.on('data', function (somedata) {  
        // if not client['data']  you might need to have a check here like this
        client['data'] = somedata;
    });    
});

I'd suggest another way, but with ECMAScript 6 weak maps

var wm = new WeakMap();

io.sockets.on('connection', function (client) {
    client.on('data', function (somedata) {   
        wm.set(client, somedata);
        // if you want to get the data
        // wm.get(client);
    }); 
    client.on('disconnect', function() {
        wm.delete(client);
    });   
});