RefreshCSS 🫧

Make your CSS so fresh, so clean.

RefreshCSS is a Python library that removes unused classes, ids, and element selectors from CSS.

🔧 Installation

pip install refreshcss

⭐️ Features

• Python library to integrate in other Python projects
• Can be used as a filter with django-compressor as part of minifying CSS

🗜️ Integrate with django-compressor

Add "refreshcss.filters.RefreshCSSFilter" to COMPRESS_FILTERS in the Django settings file.

COMPRESS_FILTERS = {
    "css": [
        "refreshcss.filters.RefreshCSSFilter",
        ...
    ],
    "js": [...],
}

🤓 How does it work?

1. Catalogue classes, ids, and elements that are currently being used in found HTML templates
2. Catalogue classes, ids, and elements in a CSS stylesheet
3. Return new CSS stylesheet that only contains rules that are actively being used by the HTML

🧐 Why?

I wanted to have a filter for django-compressor that would purge unused CSS as part of the compress step when deploying for coltrane apps. After dealing with a manual process and attempting to integrate https://purgecss.com and https://github.com/uncss/uncss I thought "this couldn't be that hard to do in Python".

Which is always the thought at the beginning of every side project... and is never accurate.

🙋 FAQ

Will this work with SPAs?

RefreshCSS only inspects HTML, so if CSS classes are being changed client-side then it will not know about it.

Does this work by crawling a website URL?

Currently no, although that is a possibility in the future.

Does this support HTML written in the Django Template Language?

Yes! That was a primary reason I built my own solution. 😅 Jinja might also be possible to support with some small tweaks, although it is untested.

Is this what people mean when they say "treeshaking"?

Maybe. 🤷

I found a bug!

Thanks for trying RefreshCSS out! Please make a PR (pull request) with a small test that replicates the bug or, if that is not possible, create a new discussion.

🤘 Related libraries

Node

• uncss
• PurgeCSS

Python

• treeshake: I unfortunately could not get this to work on my local environment
• cssutils: This unfortunately seemed to choke on more modern CSS (when I tested on Bulma 1.0)
• css-optomizer

🙏 Thanks

• Django
• django-compressor
• CSS standards

❤️ Support

This project is supported by GitHub Sponsors and Digital Ocean.