I see your point. I like to push myself to really think about the problem and how I would solve it being it a real app where even these small things can be critical in overall measure.

Clean code is surely good goal too.

Why to create RegExp everytime? You can just keep it in a closure to save some microseconds :) Also in expression itself it's not necessary to use {1}, it's implicit behavior.

Wow, did not expect someone would do it this way :)