CSSWring
A CSS minifier for PostCSS
SYNOPSIS
For readability, almost all CSS file contains a lot of white spaces, extra semicolon, etc.:
.foo {
width: 100px;
}
.bar {
margin-top: 0px;
}
.baz {
color: rgb(255, 0, 0);
background-color: rgb(36, 36, 36);
}
This PostCSS plugin removes and converts these non-essential parts of CSS file, like this:
.foo{width:100px}.bar{margin-top:0}.baz{color:red;background-color:#242424}
INSTALL
$ npm install csswring
USAGE
Of course, this package can be used as PostCSS plugin:
"use strict";
var fs = require("fs");
var postcss = require("postcss");
var css = fs.readFileSync("test.css", "utf8");
postcss([
require("autoprefixer")(),
require("csswring")()
]).process(css).then(function (result) {
fs.writeFileSync("test.min.css", result.css);
});
As standard Node.js package
To minify test.css to test.min.css:
#!/usr/bin/env node
"use strict";
var fs = require("fs");
var csswring = require("csswring");
var css = fs.readFileSync("test.css", "utf8");
fs.writeFileSync("test.min.css", csswring.wring(css).css);
As CLI Program
This package also installs a command line interface.
$ node ./node_modules/.bin/csswring --help
Usage: csswring [options] INPUT [OUTPUT]
Description:
Minify CSS using PostCSS
Options:
--sourcemap Create source map file.
--preserve-hacks Preserve some CSS hacks.
--remove-all-comments Remove all comments.
-h, --help Show this message.
--version Print version information.
Use a single dash for INPUT to read CSS from standard input.
Examples:
$ csswring foo.css
$ csswring foo.css > foo.min.css
$ cat foo.css bar.css baz.css | csswring - > fbb.min.css
When PostCSS failed to parse INPUT, CLI shows a CSS parse error in GNU error format instead of Node.js stack trace.
MINIFICATIONS
CSSWring doesn’t remove only white spaces or comments, but also remove an unnecessary parts of CSS. See minification details in our GitHub Wiki.
OPTIONS
preserveHacks
By default, CSSWring removes all unknown portion of CSS declaration that
includes some CSS hacks (e.g., underscore hacks and star hacks). If you want to
preserve these hacks, pass preserveHacks: true to this module.
postcss([
csswring({
preserveHacks: true
})
]).wring(css);
removeAllComments
By default, CSSWring keeps a comment that start with /*!. If you want to
remove all comments, pass removeAllComments: true to this module.
postcss([
csswring({
removeAllComments: true
})
]).wring(css);
API
wring(css, [options])
Wring css with specified options.
The second argument is optional. The options is same as the second argument of
PostCSS’s process() method. This is useful for generating source map.
var fs = require("fs");
var csswring = require("csswring");
var css = fs.readFileSync("from.css", "utf8");
var result = csswring.wring(css, {
map: {
inline: false
},
from: "from.css",
to: "to.css"
});
fs.writeFileSync("to.css", result.css);
fs.writeFileSync("to.css.map", result.map);
See also Source Map section in PostCSS document for more about this
options.
You can also merge CSSWring options mentioned above to the second argument:
var result = csswring.wring(css, {
map: true,
preserveHacks: true
});