What is clean-css?

Clean-css is a node.js library for minifying CSS files. It does the same job as YUI Compressor's CSS minifier but much faster thanks to many speed optimizations and the node.js itself.

Usage

What are the requirements?

node 0.6.0+ on *nix (fully tested on OS X 10.6+ and CentOS)
node 0.8.0+ on Windows

How to install clean-css?

npm install clean-css

How to use clean-css?

You can minify one file public.css into public-min.css via:

cleancss -o public-min.css public.css

To minify the same public.css into standard output skip the -o parameter:

cleancss public.css

Or more likely you would like to do something like this (if you are on *nix system):

cat one.css two.css three.css | cleancss -o merged-and-minified.css

Or even gzip it at once:

cat one.css two.css three.css | cleancss | gzip -9 -c > merged-minified-and-gzipped.css.gz

How to use clean-css programatically?

var cleanCSS = require('clean-css');

var source = "a{font-weight:bold;}";
var minimized = cleanCSS.process(source);

How do you preserve a comment block?

/*!

Important comments included in minified output.
*/

How to run clean-css tests?

You need vows testing framework (npm install vows) then simply run:

make test

on *nix systems. If you are under Windows then run:

./test.bat

Acknowledgments

• Vincent Voyer (@vvo) for a patch with better empty element regex and for inspiring us to do many performance improvements in 0.4 release.
• Isaac (@facelessuser) for pointing out a flaw in clean-css' stateless mode.
• Jan Michael Alonzo (@jmalonzo) for a patch removing node's old 'sys' package.

License

Clean-css is released under the MIT license.