Question 1

How do I ignore hover or click styles in UnCSS?

Accepted Answer

Since UnCSS only runs JavaScript on page load, you must use the ignore option in configuration or add /* uncss:ignore */ comments in your CSS to preserve selectors for dynamic states like :hover or classes added by event handlers.

Question 2

UnCSS vs PurgeCSS: which is better for React apps?

Accepted Answer

UnCSS is better if your React app injects CSS via JavaScript at runtime, as it executes JS to capture styles. PurgeCSS is faster and simpler for static content but may miss JS-injected CSS without extra configuration.

Question 3

Can UnCSS process a live website URL?

Accepted Answer

Yes, UnCSS can take URLs as input via the command line, but it requires network access and may time out on slow sites. For best results, use local HTML files or a dev server to control the environment.

Question 4

How to integrate UnCSS with Gulp for automation?

Accepted Answer

Install the gulp-uncss plugin, then add a task in your Gulpfile that specifies HTML files and options. This allows automatic CSS cleanup during builds, as shown in the README's integration examples.

Question 5

Does UnCSS work with CSS frameworks like Bootstrap?

Accepted Answer

Yes, it's ideal for optimizing Bootstrap by removing unused utility classes, but you must provide all HTML pages that use the framework to ensure necessary styles aren't stripped.

Question 6

What are common pitfalls when using UnCSS?

Accepted Answer

Over-optimizing by not accounting for dynamic content, leading to broken styles. Always test on multiple page states and use ignore rules for selectors added post-load, as recommended in the documentation.

Question 7

How to handle external CSS from CDNs with UnCSS?

Accepted Answer

Use the ignoreSheets option to exclude specific stylesheets, like Google Fonts, or include them by URL if optimization is needed. This prevents unnecessary processing of already-minified external resources.

UnCSS

What is UnCSS?

Overview

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Pros & Cons

Pros

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Frequently Asked Questions