I'm not disagreeing with you because I'm still learning JS, but as a programmer that seems wrong to me. Since you can't confirm what type the input will be, wouldn't it be best to check against undefined rather than your method? I mean again, it's clever - but would you really want to use it in production? Is it faster to make sure the input isn't falsy, AND use the code above?

Very clever, but is this a best practice? It's not immediately clear what's going on, whereas the other solutions are.

Doesn't give enough information on failed test cases, like the array passed in, what the result was, etc.

In hindsight, I didn't need to reverse the array, however I started off using .forEach rather than for, and kept the array reversed just... Because.