> Just curious. Have you benchmarked what it would be w/o the check?

I tried it, and it doesn't make a difference (not above the noise at least).

> Also, I know it's not your code, but since you're here. Can you change it to exports.join = function join() {. Unnamed functions are such a pain to track down with performance benchmarking.

All the functions in the module are anonymous, so it'd be inconsistent if I changed it only for this one. May I suggest you add names to all the functions in a separate commit?