yep, but if you've already mastered all the logic behind the simple permutation, sometimes using a stl function would come with less TC compared to coding on your own. This solution provides some insights with me, though I still deem it cheating XD

If one has a linked list with tens of thousands of records in Javascript, I think that's likely a problem bigger problem than this function blowing out the stack.

Though, I am disappointed to learn that most browsers haven't implemented tail recursion optimization, even though it was in the ES2015 spec nearly 10 years ago. It's such a boilerplate program optimization, I'd assumed it would have happened by now. Go Safari, I guess.