It's the future now and there are a lot of solutions again. Also, the quality of all of the solutions is much better.

Hmm... this appears to kill all but 3 of the solutions...

Added.

That kind of is the point

this method is so sketchy

:O

:/

Why reverse?

I was put off, at first, but then gave it a shot and solved it.

However, I'm not sure if my simple solution is "really correct" or if it just passes the kata tests. For example, the test cases provided "pre-attampt" actually fail for my answer, but I was curious and clicked attempt and my code passed. Either the pre-attempt tests are wrong or overly strict, or the solution tests are incorrect or overly loose.

If you want to ratchet up the difficulty one notch, add a test case with comments in the function definition:

function addComments(/* comments */ a,b) { return a+b; }
var addComments_ = defaultArguments(addComments,{b:9});
Test.assertEquals(addComments_(10), 19, "addComments_(10)");