socket.io socket.set and socket.get - what is the callback argument for?
node.js, socket.io
Solution
`set` and `get` are asynchronous. The callback will be called when these operations are completed. You can omit it, or you can use it for whatever purpose you like, not just error handling.
Problem
I just want to attach some variables to my sockets, but I don't understand the .get and .set methods. They both have a third argument for a callback. Can this be omitted? What is it for?! Does the callback itself intherit arguments? My best guess is that it's there for when socket.io isn't using memory store but is saving this stuff somewhere else and needs an error checking callback. ``` socket.on('set nickname', function (name) { socket.set('nickname', name, function (arguments) { doSomethingMysterious(); }); ``` I'm using socket.io 0.9.x The function is defined in socket.js ``` /** * Stores data for the client. * * @api public */ Socket.prototype.set = function (key, value, fn) { this.store.set(key, value, fn); return this; }; ```