I came up with a similar solution but did not put the second arguments in quotes. Is there practical difference?

A negative index will eventually throw a NullPointerException when the nodes run out.

Thanks for explanation ( ͡° ͜ʖ ͡°)s

mine)))

I wanted to do this but couldn't perform a double regex by && || but couldn't think of this, brilliant.

I think the split and map methods are being upvoted because this is an arrays kata.

This is the simplest answer. Don't know why people are upvoting the split and map method.

I have done the same.

Didn't know is possible to specify a range of numbers [0-9] in Regex,
the most clear and simple.

Shall we add a proper testcase to include these edge cases? :) thanks for your feedback!

What if a negative index is passed in?

Thank you for no JSON.stringify()