[nxn]

You mean the nested versions? Just because it's not the most efficient way possible to do something does not automatically mean it's a 'performance issue'. If you're doing it once, or if it's some user based event like a button click, the difference will not be noticeable. If this is happening in a loop, perhaps then you might be in need of re-factoring. But in this example it would probably hardly help since it's reading and writing files, and chances are that's going to slow you down more.

EDIT: took out function hoisting stuff, it doesn't get hoisted after a quick check.