You can't really. Especially in JavaScript world where velocity is everything. You'd spend at least ~1 year if it is really large and hit all kinds of hacks in

You can't really. Especially in JavaScript world where velocity is everything. You'd spend at least ~1 year if it is really large and hit all kinds of hacks in the form of callbacks within callbacks within callbacks that are tuned in a way that (mostly) works. I'd recommend you to run away, seriously.