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p/purgecssEasily remove unused CSS
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Floriel Fedry

Purgecss - Easily remove unused CSS

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When you are building a website with a css framework like Bootstrap, you will only use a part of the framework and unused css styles will be included.

Purgecss removes unused selectors from your css, resulting in smaller files.

"With PurgeCSS, you'll have a hard time generating CSS that isn't under 10kb minified and gzipped." - Tailwindcss docs

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Hristiyan Dodov
How does it handle JavaScript-generated elements, though? It appears that it digs in your HTML, compares it with your CSS and removes unnecessary stuff. But what if you append an element with jQuery and give it a class `js-my-button`? It wouldn’t be in your HTML so any styles applied to it in your CSS would be removed? 🤔 Nick DeNardis says in his article that it "is searching through all .html, .blade.php, .js and .vue files" but it seems suspicious to me. There are so many ways to create elements in JS and style them. How does it guarantee that it won’t stab you in the throat by removing something that’s actually used?
Floriel Fedry
Maker
@hristiyandodov Purgecss was designed to be modular and works with every type of files. One of the step of the process is to get the used selectors in the content files (e.g. js). By default, it will look into each word in the file and consider it a selector. So if you add a class with jquery `.addClass(“js-my-button”)`, `js-my-button` will be register as a used selector. You can customize this behavior and provide a function to select the selector in the file.
Hristiyan Dodov
@ffloriel_ Alright, but what if the class name is formed on runtime through a variable like that: $elem.addClass("js-my-" + name); Would it leave all rules that contain `js-my-`?
Floriel Fedry
Maker
@hristiyandodov With the default settings, it will not consider `js-my-button` used and will remove the css. There are a few options to go around this problem. One is to whitelist the selector. The second one is to create a custom extractor. I am experimenting with it at the moment in the purgecss-from-js repo. The idea is to use prepack the code and generate the classname so that Purgecss can find them. Links: whitelisting in purgecss: https://www.purgecss.com/whiteli... purgecss-from-js: https://github.com/FullHuman/pur... Facebook prepack: https://prepack.io/
Edward Vasquez
purgecss also works with grunt, angular?
Floriel Fedry
Maker
@edwardvasquezdr Purgecss is framework agnostic. It is not specific to a framework or plateform. There is currently no grunt plugin for it. Purgecss is available via a CLI, a javascript API, Webpack, Gulp and Rollup plugins. I will add Grunt shortly.
Floriel Fedry
Maker
@edwardvasquezdr @ptothaointi It is still a work in progress but the grunt plugin is available here: https://github.com/FullHuman/gru...
Pointi
@ffloriel_ @edwardvasquezdr hey, did you get it working with grunt?
Daniel Cardoso
What are the main differences between Purgecss and purifycss?
Floriel Fedry
Maker
@drbcardoso You can see Purgecss as an updated version of PurifyCSS. Purgecss does not have the issues of PurifyCSS. You can also find information on the documentation about the differences. Purifycss is also not actively maintained anymore. Links: purifycss issues: https://github.com/purifycss/pur... comparison: https://www.purgecss.com/compari...
Özlem D.

I love it.

Pros:

easy to use, useful tool for frontend

Cons:

maybe the scope can be extend

Ashish Kumar

Works exactly as expected in the first go.

Pros:

Quite handy

Cons:

None

Steven J. Selcuk
I love this! 😍
Andrew Tye
I've wanted something like this forever! If you can also incorporate a feature to show how many times something is used that would be an extra bonus.
Primer
I like this a lot. Thanks for making.
Santi

Awesome and easy tool to improve performance

Pros:

Easy to use

Cons:

At this moment anything

Seth Hawkins
Such a needed resource for web developers. It can be so tough to keep track of the CSS you're not using anymore that is dragging down your page load times and unnecessarily complicating your code.
Shriya Nevatia
I'm trying to use Purgecss now and I think it's getting stuck on sass variable names; do you know if that's the issue if I'm getting errors like "CssSyntaxError: :16:12: Unknown word"?