Fixed in latest fork above

Well, it is kinda implied by this sentence :

It's guaranteed that each person has 2 legs and each cat has 4 legs.

Not all strings will contain digits and not all inputs will be string. In those cases, return -1.

Rewrote more explicitly now.

Fixed in this fork

Not all strings will contain digits. In this case and the case for any non-strings, return -1.

It could be clearer indeed but it is mentionned.
Here's a JS fork modifying the description. Hope it is better

fixed

done at some point

done there

Fixed in this fork

Fixed in this fork

done

what random tests could there be ? it's a singleton class with no methods or properties to test.

added to both CS and JS

done

Updated to v18