It would be better to replace false : true with === 0;

Similar to mine but yours is way cleaner, wish I had thought of it!

Yeah I'm still pretty new to Codewars and programming in general, so I was thinking that modifying objects in place here wouldn't really matter, since I figured the string wasn't going to be used again after I ran the code, so I didn't realize it would affect the expected strings in the test cases. I spent so much time trying to figure out what was going wrong! Thanks for your help, I will definitely be more careful from now on!

We mixed our posts. If I correctly understand you modified the input string in place? Wow, bad practice:-))

Oh wow, I didn't even think about that haha! That fixed it right away. Thanks a lot and sorry for reporting an issue!

Example tests: you have testing(decode($data2Sol), $data2).
In the example tests you can see yourself that decoding $data2Sol gives exactly $data2, the \v are not kept and what you get is correct.
The expected you had had doesn't correspond to the given solution of the example tests!

I don't understand what happened:-( I tried a few solutions already passed, I printed the results and everything was correct.

Edit: your solution passed so why an issue?

Thanks!

Wow, floating point arithmetic in JS messed me up on this one! Thanks for the challenge, learned a lot!

Try logging your stack to the console. Your code has a bug.

Rewrote so that methods were defined on prototype