Seeing the description and the tests, what other possibility other than strings there is?

PHP
Write to description return type you want from this functions in tests. I done this but this guessing takes more time than main task.

I see now. Either @jkalasz can fix something (maybe), or this kata will get retired (expecting it fairly soon, as one more downvote will do it).

At the moment, this function is not very mysterious at all.

The mystery return value for "2" is "2". For ( Number ) 2, it is "2". JSON.stringify does not have that information loss.

That's worse. I'm comparing mystery to JSON.stringify here, and the latter is doing better. No?

Not blaming you; my problem is with the whole concept of the kata. I don't know PHP; it may work there, I don't know, but I think it doesn't work in JS.

for a worse result.

I still don't get it, sorry. But, now I see it's the same with PHP, I just transpiled it over.

@jkalasz's fault I guess ヽ༼ຈل͜ຈ༽ﾉ

You solved it, so something works.

The fact that I jumped through a hoop does not mean the task works as a kata.

What is the added value of the return value from this function over the return value of JSON.striongify(arguments) ?

mystery("2") is supposed to give the same return value as mystery(2), so I see no added value, only subtracted value: more work for a worse result.

You solved it, so something works.

You've reinvented JSON.stringify

Sorry, I don't see how I did that.

the difference between String "2" and Number 2 gets lost - at the cost of additional, totally unnecessary complexity

I just don't get it. (I created the JS translation)

( JS )

You've reinvented JSON.stringify, but worse, because the difference between String "2" and Number 2 gets lost - at the cost of additional, totally unnecessary complexity. I don't know if this kata works in PHP, but in JS, it doesn't.

I don't know whether to label this an issue, a suggestion ( to unpublish ), a question ( what's the meaning of life, the universe and this kata? ) or not at all. So I won't.

Sounds like you fixed it. ( ͡ᵔ ͜ʖ ͡ᵔ )

It should be more clear now, as it should be in the same order as cpecified in the object. (. ❛ ᴗ ❛.)

＼(^_^ )

JS translation kumited. ( ͡° ͜ʖ ͡°)