Running Tailwind on variable

[silicahd]

My system is a running on Laravel. However I am trying to figure out how to run purgecss on a variable. This is because my application is a page builder that submits the data via post. It than saves it to a database along with the css used. So far I am running bootstrap so it is easy to write my own parser, but with tailwind it seems a bit more challenging.

I am also trying to set this to be able to run it in a controller, rather than running laravel mix.

Anybody has any idea how to accomplish this?