Reported as issue.

Yes. This is it. Generating a huge range this way just isn't going to work, apparently. The .slice() doesn't help, but I don't know if that's the actual problem.

Array.from( { length: n }, (_,i) => i+1 ).filter().length

would be more understandable, and more efficient because of no .slice(), than your code. I had to do some very careful reading to understand how that worked. It's ingenious, but not very flexible or maintainable.

Sadly we can't downvote the best practices... But this solution does not work, and should not be accepted as a proper solution.

You're absolutely right.

This solution should not work with "baconnnnnnnnnnn" and "bacon".

Ok, its the size of the array generated.

Are any function similar to Python "xrange" for Javascript?

Test cases should include floats and negative numbers.