Skud Pai Sho is the most accessible, playable, and complete ruleset for Pai Sho. Play online and learn more at The Garden Gate - SkudPaiSho.com.
I recommend using VSCode or a similar editor to work in.
This npm package is needed:
npm install uglify-js -g
Then, run the minify script to "compile" the javascript code and update the index.html to reference the updated code. Also run this whenever you want to test any changes.
./minify
Then open up the index.html file (on a Mac, I've found that Safari's dev tools work the best - Chrome and Firefox freeze up for me).