Order of execution issue javascript

Question

In my code below, 5 always prints before 4. I thought because the callback to postUsers was in a return statement from matchAgainstAD it would wait

Answer 1

ad.findUser takes a callback that contains the console.log(4). That function is async, and will hit your callback when the IO operation has completed.

On the other hand, postUsers is called completely synchronously, so it will hit console.log(5) before ad.findUser enters your callback.

A simple way to fix this is to call postUsers from inside of your ad.findUser callback.

I would suggest looking into the promise pattern for JavaScript to manage dependencies between async operations. There are several popular libraries (Q and RSVSP.js being a couple of them).