csso
Advanced tools
Package description
CSSO (CSS Optimizer) is a CSS minifier. It performs three kinds of optimizations: structural optimizations, reducing CSS size by merging blocks with identical properties, removing overridden properties, etc.; cleaning (removing unused @media rules, cutting out the comments, etc.); and compressing (transforming values to shorter forms, merging identical selectors, etc.). It can be used as a command-line tool or as a library.
Minification
Minifies CSS by removing whitespace, comments, and making other optimizations to reduce file size.
const csso = require('csso');
const minifiedCss = csso.minify('.test { color: #ff0000; }').css;Structural Optimization
Optimizes CSS structure by merging blocks with identical properties and removing overridden properties.
const csso = require('csso');
const optimizedCss = csso.minify('.test { color: red; } .test { font-size: 16px; }', { restructure: true }).css;Source Map Generation
Generates a source map that can be used to debug the minified CSS by mapping it back to the original sources.
const csso = require('csso');
const result = csso.minify('.test { color: red; }', { sourceMap: true });
const minifiedCss = result.css;
const map = result.map.toString();clean-css is a fast and efficient CSS optimizer for Node.js and the Web. It provides similar minification capabilities as CSSO but also offers advanced optimizations like restructuring.
uglifycss is a CSS minifier that aims to be fast and simple. It doesn't have as many features as CSSO, focusing mainly on removing whitespace and comments to compress CSS files.
purifycss is a tool to remove unused CSS. Unlike CSSO, which focuses on optimizing existing CSS, purifycss analyzes your content and CSS files to remove unused selectors.
Changelog
1.5.0 (January 14, 2016)
gonzales→internal and internal→gonzales convertors, walkers, translator)@media with same queryoutputAst – new option to specify output AST format (gonzales by default for backward compatibility)from→0% and 100%→to at @keyframes (#205)@keyframes (#80, #197)gonzales AST was implemented--stat (output stat in stderr)level for --debug optionReadme
CSSO (CSS Optimizer) is a CSS minimizer unlike others. In addition to usual minification techniques it can perform structural optimization of CSS files, resulting in smaller file size compared to other minifiers.
npm install -g csso
csso [input] [output] [options]
Options:
--debug Output intermediate state of CSS during compression
-h, --help Output usage information
-i, --input <filename> Input file
-o, --output <filename> Output file (result outputs to stdout if not set)
--restructure-off Turns structure minimization off
-v, --version Output the version
Some examples:
> csso in.css out.css
> csso in.css
...output result in stdout...
> echo ".test { color: #ff0000; }" | csso
.test{color:red}
> cat source1.css source2.css | csso | gzip -9 -c > production.css.gz
var csso = require('csso');
var compressed = csso.minify('.test { color: #ff0000; }');
console.log(compressed);
// .test{color:red}
// you may do it step by step
var ast = csso.parse('.test { color: #ff0000; }');
ast = csso.compress(ast);
var compressed = csso.translate(ast, true);
console.log(compressed);
// .test{color:red}
// There are two options you can pass
var compressedWithOptions = csso.minify('.test { color: #ff0000; }', {
restructuring: false, // don't combine same selectors
debug: true // show additional debug information
})
May be outdated
FAQs
CSS minifier with structural optimisations
The npm package csso receives a total of 8,818,115 weekly downloads. As such, csso popularity was classified as popular.
We found that csso demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 3 open source maintainers collaborating on the project.
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