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specificity
Advanced tools
The 'specificity' npm package is used to calculate the specificity of CSS selectors. Specificity is a measure of how specific a CSS selector is, which determines which styles are applied when multiple selectors match the same element.
Calculate Specificity
This feature allows you to calculate the specificity of a given CSS selector. The result will be an array of objects, each containing the selector and its specificity score.
const specificity = require('specificity');
const result = specificity.calculate('body div #content .article');
console.log(result);
Compare Specificity
This feature allows you to compare the specificity of two CSS selectors. The comparison result will indicate which selector is more specific.
const specificity = require('specificity');
const result1 = specificity.calculate('body div #content .article');
const result2 = specificity.calculate('body div .article');
const comparison = specificity.compare(result1[0].specificityArray, result2[0].specificityArray);
console.log(comparison);
The 'css-specificity' package also calculates the specificity of CSS selectors. It provides similar functionality to 'specificity' but with a different API. It is useful for developers who need to analyze and compare CSS selector specificity.
The 'css-selector-parser' package parses CSS selectors and can be used to analyze their structure. While it does not directly calculate specificity, it can be used in conjunction with other tools to achieve similar results.
A JavaScript module for calculating and comparing the specificity of CSS selectors. The module is used on the Specificity Calculator website.
Specificity Calculator is built for CSS Selectors Level 3. Specificity Calculator isn’t a CSS validator. If you enter invalid selectors it will return incorrect results. For example, the negation pseudo-class may only take a simple selector as an argument. Using a psuedo-element or combinator as an argument for :not()
is invalid CSS3 so Specificity Calculator will return incorrect results.
SPECIFICITY.calculate('ul#nav li.active a'); // [{ specificity: '0,1,1,3' }]
var specificity = require('specificity');
specificity.calculate('ul#nav li.active a'); // [{ specificity: '0,1,1,3' }]
You can use comma separation to pass in multiple selectors:
SPECIFICITY.calculate('ul#nav li.active a, body.ie7 .col_3 h2 ~ h2'); // [{ specificity: '0,1,1,3' }, { specificity: '0,0,2,3' }]
The specificity.calculate
function returns an array containing a result object for each selector input. Each result object has the following properties:
selector
: the inputspecificity
: the result as a string e.g. 0,1,0,0
specificityArray
: the result as an array of numbers e.g. [0, 1, 0, 0]
parts
: array with details about each part of the selector that counts towards the specificityvar specificity = require('../'),
result = specificity.calculate('ul#nav li.active a');
console.log(result);
/* result =
[ {
selector: 'ul#nav li.active a',
specificity: '0,1,1,3',
specificityArray: [0, 1, 1, 3],
parts: [
{ selector: 'ul', type: 'c', index: 0, length: 2 },
{ selector: '#nav', type: 'a', index: 2, length: 4 },
{ selector: 'li', type: 'c', index: 5, length: 2 },
{ selector: '.active', type: 'b', index: 8, length: 7 },
{ selector: 'a', type: 'c', index: 13, length: 1 }
]
} ]
*/
Specificity Calculator also exposes a compare
function. This function accepts two CSS selectors or specificity arrays, a
and b
.
-1
if a
has a lower specificity than b
1
if a
has a higher specificity than b
0
if a
has the same specificity than b
SPECIFICITY.compare('div', '.active'); // -1
SPECIFICITY.compare('#main', 'div'); // 1
SPECIFICITY.compare('span', 'div'); // 0
SPECIFICITY.compare('span', [0,0,0,1]); // 0
SPECIFICITY.compare('#main > div', [0,1,0,1]); // 0
You can pass the SPECIFICITY.compare
function to Array.prototype.sort
to sort an array of CSS selectors by specificity.
['#main', 'p', '.active'].sort(SPECIFICITY.compare); // ['p', '.active', '#main']
Run npm install specificity
to install the module locally, or npm install -g specificity
for global installation. You may need to elevate permissions by sudo
for the latter. Run specificity
without arguments to learn about its usage:
$ specificity
Usage: specificity <selector>
Computes specificity of a CSS selector.
Pass a selector as the first argument to get its specificity computed:
$ specificity "ul#nav li.active a"
0,1,1,3
To install dependencies, run: npm install
Then to test, run: npm test
FAQs
Calculate the specificity of a CSS selector
The npm package specificity receives a total of 1,785,659 weekly downloads. As such, specificity popularity was classified as popular.
We found that specificity demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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