You can use native JavaScript methods to work with regular expressions:
https://www.w3schools.com/js/js_regexp.asp
Same probably goes for color conversion and other common C3 functions.
Thank for your reply, but I've meant rgbEX not regex! ^_^ It's about color object :)
I need it for using `BetterOutline` filter (https://www.construct.net/en/make-games/addons/449/better-outline) as I want to set its value programmatically via JavaScript and it cannot take a string as a value (getting Type mismatch error)