closing as user error. The user likely created a regexp dynamically without escaping special characters.

I used Java, I am new to this language but yet I did come at end to a string that in System.out.println(thatString) show this for the test ")()())()(()()(" but for returning that string, like return thatString; , I have an eror "Unclosed group near index 1, ( " . I even hardcoded this string at return for test, and I have this eror anyway. I did an Array, a List and a String Builder and then all of them transformed to String, nothing seems to work...

Thanks!

Sorry, working on other things at the moment.

May I recommend the documentation for your attention? There's heaps of information on writing your first kata there, and more on writing kata in general.

If you can help me with improving this kata, please! I'll be grateful to have some help from somebody more experienced! For me this type of exercise as a beginner was interesting to do and challenging. Hope somebody gonna find it the same!

In JavaScript, what you are asking is not forbidden or even strictly wrong.

But I don't like mixing types in arrays ( when used as lists, which is what you're doing; not when used as tuples, which it is not ), I hate implicit coercion ( comparing strings as numbers ), and I hate inconsistent typing ( which is what you're doing with [[1,1,1],4] ).

Not an Issue, just an FYI, and not why I downvoted the kata. ( If description and testing are improved to impeccability, I might remove my vote. I will not upvote a kata that plays this loose with types. It's just not my cup of tea. )

Your random tests are vulnerable to input modification.

It is documented what this means, why it's bad and how to prevent it.

expected [ Array(11) ] to deeply equal [ Array(9) ]

This is not a useful failure message. Set chai.config.truncateThreshold.

This is documented.

Maybe you should let somebody else write your description then. There's no shame in not being a theory guy, but it's not an excuse for an inadequate description.

Thanks, I.m gonna work on that. I.m not such a theory guy, more of a practice and real eaxmples guy.

The description doesn't seem to be missing any info like it did, but it is still very poorly structured, all the specs should be clearly defined and listed together without relying on examples.

Can you review please my describing of the task and say if it.s ok now, maybe some changes to make, or what improvments to give to the kata? Thanks again!

Thanks for feedback! Did that already, but for some reason after Re-Publish(ing) nothing happens, I.ll try later again.

Global variables should be removed from tests.