CSS selectors complexity and performance analyzer
BSD-2-CLAUSE License
CSS selectors complexity and performance analyzer. analyze-css is built as a set of rules bound to events fired by CSS parser. Each rule can generate metrics and add "offenders" with more detailed information (see Usage section for an example).
analyze-css comes as a "binary" for command-line and as CommonJS module. Run the following to install them globally:
npm install --global analyze-css
or to install from GitHub's repository:
npm install --global @macbre/analyze-css
You can use analyze-css "binary" to analyze local CSS files or remote CSS assets:
$ analyze-css --file examples/elecena.css
$ analyze-css --url http://s3.macbre.net/analyze-css/propertyResets.css
$ analyze-css --url https://s3.macbre.net/analyze-css/propertyResets.css --ignore-ssl-errors
You can provide CSS via stdin as well (notice the dash: -
):
$ echo ".foo {margin: 0 \!important}" | analyze-css -
This will emit JSON formatted results on stdout
. Use --pretty
(or -p
shortcut) option to make the output readable for human beings.
Basic HTTP authentication can be provided through the options --auth-user
and --auth-pass
.
HTTP proxy (e.g. http://localhost:8080
) can be provided via:
--proxy
or -x
optionHTTP_PROXY
env variablenpm i --save analyze-css
const analyze = require('analyze-css');
(async() => {
const results = await analyze('.foo {margin: 0 !important}');
console.log(results); // example? see below
})();
// options can be provided
const opts = {
'noOffenders': true
};
(async() => {
const results = await analyze('.foo {margin: 0 !important}', opts);
console.log(results); // example? see below
})();
Created by @DeuxHuitHuit
$ npm i grunt-contrib-analyze-css
It uses configurable threshold and compares the analyze-css result with it.
{
"generator": "analyze-css v0.10.2",
"metrics": {
"base64Length": 11332,
"redundantBodySelectors": 0,
"redundantChildNodesSelectors": 1,
"colors": 106,
"comments": 1,
"commentsLength": 68,
"complexSelectors": 37,
"duplicatedSelectors": 7,
"duplicatedProperties": 24,
"emptyRules": 0,
"expressions": 0,
"oldIEFixes": 51,
"imports": 0,
"importants": 3,
"mediaQueries": 0,
"notMinified": 0,
"multiClassesSelectors": 74,
"parsingErrors": 0,
"oldPropertyPrefixes": 79,
"propertyResets": 0,
"qualifiedSelectors": 28,
"specificityIdAvg": 0.04,
"specificityIdTotal": 25,
"specificityClassAvg": 1.27,
"specificityClassTotal": 904,
"specificityTagAvg": 0.79,
"specificityTagTotal": 562,
"selectors": 712,
"selectorLengthAvg": 1.5722460658082975,
"selectorsByAttribute": 92,
"selectorsByClass": 600,
"selectorsById": 25,
"selectorsByPseudo": 167,
"selectorsByTag": 533,
"length": 55173,
"rules": 433,
"declarations": 1288
},
"offenders": {
"importants": [
".foo {margin: 0 !important}"
]
}
}
body .foo
, section body h2
, but not body > h1
)ul li
, table tr
)header ul li .foo
).foo { }
)expression( document.body.clientWidth > 600 ? "600px" : "auto" )
)* html .foo {}
and .foo { *zoom: 1 }
, read more)@import
rules!important
@media screen and (min-width: 1370px)
)span.foo.bar
)--moz-border-radius
)header#nav
, .foo#bar
, h1.title
).foo, .bar { color: red }
is counted as two selectors - .foo
and .bar
).foo .bar, #test div > span { color: red }
will be set as 2.5).foo[value=bar]
):hover
).foo, .bar { color: red }
is counted as one rule).foo, .bar { color: red }
is counted as one declaration - color: red
)Running tests and linting the code:
$ npm test && npm run-script lint
Turning on debug mode (i.e. verbose logging to stderr via debug module):
$ DEBUG=analyze-css* analyze-css ...