What if you got input like tHe-caMEL-Case

You can also just add the i case insensitive flag to your RegExp. Also, you don't need block parameter x

I wanted this hahahha but couldn't make it. I got stuck on how to reference. tried gsub(/regex/, '\1'.capitalize). no success and no succes when passed as block.

Very nice

@DaltheCow the most important part in that regex, (.), is the parentheses though, which captures the . ("any character except newline") and feeds it into $1.

I assume you mean [a-zA-Z] and yes that's required to match upper case letters after the symbols.

pretty basic regex so you should probably read up on them and practice (I suggest eloquent javascript chapter 9).
The . means any character except newlines

You can't just switch out the . for [a-z], you have to do [a-z||A-Z]

I used [a-z] in mine as you don't want to .upcase on non-letters.

The letter after the underscore/hyphen matched in the regex.

There are brackets around the full stop, those brackets are what you can reference with $1 and so on.

What is $1?

What is $1?

The string interpolation is unnecessary. You can just do $1.upcase

Very smart!