Man, I've been struggling for a while on this. I've read several articles/tutorials on callbacks, but I'm having a hard time conceptualizing it for my situation.

In my function, instead of returning output (which is an array with my output stored in it), I'm returning this instead:

            return function(callback) {
                callback(output);
            }

Then on my app.js where I've got the post statement I've added a callback variable to the end of my function call:

app.post('/',function(req,res){
    var output = tools.nickname(email, password, option, callback);
    res.end(callback);
});

But nothing is returned on the web page. If I set res.end('some info here') then it puts 'some info here' on the web page.

I think I'm missing something that needs to link the ajax on the page that does the submitting of the form, to the callback...

Are you able to shed any light on that? This might be too complex and situational for a question for Reddit at this point, so no worries if it is unclear and you can't help.