are you referring to the index starting at 0

I was conflicted about that with confusing programmers. I figured there is enough context to understand that the index count started at 0.

If you can find my documentation that advises to not do that I can update it.

As for the check digit X I avoided it in the random tests for rust be could be an extra worth while challenge.

will add random tests for js

I think if ISBN-13 is novel enough for its own specification it is unique enough to combine it with a narrative and a more complex problem.

Yes as a 2nd Dan with 133k honor I understand how this isnt unique enough to you. But if we judge this based solely on how novel it is to a power user we should just delete most of 6kyu and below because they are all boiled down to an iterator with some maths.

JS version has no random tests.

The formula for ISBN-10 as written by the description isn't even correct, since it starts at 0.

And where is X? X is a possible check digit too, so it should be tested (though then you'll have to figure out how to make the "remove junk character" part work).

Okay, so you know that ISBN-10 is already done, but ISBN-13 is barely any different from Luhn algorithm with *2 replaced by *3 (and CW has Luhn too), and the "remove junk character" part is barely a notable addition to the kata.

So what is the actual part of the kata that can be considered novel? It looks just like a combination of duplicates.

Added an actual Javascript version with tests

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No worries. You'd be surprised how common it is actually.

Ah thank you sorry about that, new to submitting challenges. Thanks for catching that

No, you've accidentally published a JavaScript version alongside the rust version.

Are you referencing ISBN-10 Validation?

I view this as a different problem given the addition of ISBN-13 and fuzzy string manipulation.

There's an unintended JavaScript version of this kata. You should remove that.

Oh lovely, I didn't know you could do that with =n to make it inclusive.