si13b/cssgzmin

A port of barryvan's GZip optimised CSS Minifier to JS

CSS GZip Minifier

A port of barryvan's CssMin Java project to JavaScript/NPM.

From the CSSMin github README:

What is it?

CSSMin takes your CSS file and strips out everything that's not needed -- spaces, extra semicolons, redundant units, and so on. That's great, but there are loads of programs that do that. A shell script could do that! So what makes CSSMin different?

When you deliver content over the web, best practice is to deliver it gzipped. CSSMin takes your CSS file, and optimises it for gzip compression. This means that there's a smaller payload delivered over the wire, which results in a faster experience for your users. It does this optimisation by ensuring that the properties inside your selectors are ordered consistently (alphabetically) and in lower case. That way, the gzip algorithm can work at its best.

What this means in practice is that your gzipped CSSMin-ed files are significantly smaller than plain gzipped CSS, and noticeably smaller than files that have been compressed by other means (say, YUI).

What does it do?

• Replaces font-weight values like 'bold' with their numeric counterparts;
• Strips quotes wherever possible;
• Changes as much of the contents to lowercase as possible;
• Strips all comments from the source;
• Removes unnecessary whitespace; and, most importantly,
• Reorders the properties within your selectors alphabetically.

Usage as a command line tool

Install:

npm install -g cssgzmin

Usage:

cssgzmin infile [outfile]

Will write to stdout if outfile omitted

Usage as a module

Install

npm install --save cssgzmin

Usage:

const minify = require('cssgzmin').minify;

console.log(minify('.somerule { border: 0px; } .morerules { background: darkblue; }'));

Requirements

This tool was written for NodeJS 6+, to take advantage of ES6 features. Running the source through Babel would probably allow it run with older versions of Node. If there's high enough demand I'll consider making that a permanent build step.

Contributors

cssgzmin is as port of CSSMin to JavaScript/NPM, which was originally written, and is maintained by, Barry van Oudtshoorn. See CssMin for a full list of contributors to the original project.

This JavaScript port was originally written by, and is maintained by, Simon Bracegirdle.

License

cssgzmin is licensed under the BSD License. See LICENSE for details.

cssgzmin's Issues

Publish to npm

And also...

• Test CLI after npm install -g on fresh system
• Test module import in fresh project

Colour code reduction strips surrounding value parts

e.g. 2px dotted #cccccc can be reduced to 2px dotted #ccc, but instead it's reduced to #ccc.

CI should run linter also

i.e. npm run lint should have 0 exit code

Empty CSS rules should be discarded

e.g.

body {}

Should be excluded entirely

Vendor prefixed properties should always appear before standard properties

e.g.

-webkit-blah: 0;
blah: 0;

instead of:

blah: 0;
-webkit-blah: 0;

Should strip whitespace surrounding comma separated selectors

e.g. html, body {} can be reduced to html,body{}, but instead it's reduced to html, body{}.

Convert to hexcode from rgb() in some circumstances

As per https://github.com/barryvan/CSSMin/blob/master/CSSMin.java (line 428), in some cases rgb values can be converted to the equivalent hex-code to save space.

e.g. convert rgb(51,102,153) to #336699

Error when attempting to strip comments

Comments not being stripped in sheetProcessor, causing errors downstream in ruleProcessor

1) sheetProcessor tests should minify test.advanced.css:
     Uncaught Error: Found 1 parts, expected exactly 2 for line ( /* Ooooh, a media query */
        )