Parses stylesheets and returns an object with statistics. This is the core module used in cssstats.com

npm i --save cssstats

var fs = require('fs')
var cssstats = require('cssstats')

var css = fs.readFileSync('./styles.css', 'utf8')
var stats = cssstats(css)

CSS Stats can be used as a PostCSS plugin. The stats will be added to PostCSS's messages array.

var fs = require('fs')
var postcss = require('postcss')
var cssstats = require('cssstats')

var css = fs.readFileSync('./styles.css', 'utf8')
postcss()
  .use(cssstats())
  .process(css)
  .then(function (result) {
    result.messages.forEach(function (message) {
      console.log(message)
    })
  })

Options may be passed as a second argument.

var stats = cssstats(css, { mediaQueries: false })

• safe (boolean, default: true) - enables PostCSS safe mode for parsing CSS with syntax errors
• mediaQueries (boolean, default true) - determines whether or not to generate stats for each media query block
• importantDeclarations (boolean, default false) - include an array of declarations with !important

The following options add the results of helper methods to the returned object. This is helpful when using JSON.stringify().

• specificityGraph (boolean, default false)
• sortedSpecificityGraph (boolean, default false)
• repeatedSelectors (boolean, default false)
• propertyResets (boolean, default false)
• vendorPrefixedProperties (boolean, default false)

// Example
{
  size: n,
  gzipSize: n,
  rules: {
    total: n,
    size: {
      graph: [n],
      max: n,
      average: n
    }
  },
  selectors: {
    total: n,
    id: n,
    class: n,
    type: n,
    pseudoClass: n,
    psuedoElement: n,
    values: [str],
    specificity: {
      max: n
      average: n
    },
    getSpecificityGraph(),
    getSpecificityValues(),
    getRepeatedValues(),
    getSortedSpecificity()
  },
  declarations: {
    total: n,
    unique: n,
    important: [obj],
    properties:
      prop: [str]
    },
    getPropertyResets(),
    getUniquePropertyCount(),
    getPropertyValueCount(),
    getVendorPrefixed(),
    getAllFontSizes(),
    getAllFontFamilies(),
  },
  mediaQueries: {
    total: n,
    unique: n,
    values: [str],
    contents: [
      {
        value: str,
        rules: {
          total: n,
          size: {
            graph: [n],
            max: n,
            average: n
          }
        },
        selectors: {
          total: n,
          id: n,
          class: n,
          type: n,
          pseudoClass: n,
          pseudoElement: n,
          values: [str],
          specificity: {
            max: n,
            average: n
          }
        },
        declarations: {
          total: n,
          unique: n,
          important: [obj],
          vendorPrefix: n,
          properties: {
            prop: [str]
          }
        }
      }
    ]
  }
}

The size of the file in bytes

The size of the stylesheet gzipped in bytes

• total number - total number of rules
• size object
  • size.graph array - ruleset sizes (number of declarations per rule) in source order
  • size.max number - maximum ruleset size
  • size.average number - average ruleset size

• total number - total number of selectors
• type number - total number of type selectors
• class number - total number of class selectors
• id number - total number of id selectors
• pseudoClass number - total number of pseudo class selectors
• pseudoElement number - total number of pseudo element selectors
• values array - array of strings for all selectors
• specificity object
  • specificity.max number - maximum specificity as a base 10 number
  • specificity.average number - average specificity as a base 10 number
• getSpecificityGraph() function - returns an array of numbers for each selector’s specificity as a base 10 number
• getSpecificityValues() function - returns an array of selectors with base 10 specificity score in order
• getRepeatedValues() function - returns an array of strings of repeated selectors
• getSortedSpecificity() function - returns an array of selectors with base 10 specificity score, sorted from highest to lowest

• total number - total number of declarations
• unique number - total unique declarations
• properties object - object with each unique property and an array of that property’s values
• getPropertyResets() function - returns an object with the number of times margin or padding is reset for each property
• getUniquePropertyCount(property) function - returns the number of unique values for the given property
• getPropertyValueCount(property, value) function - returns the number of times a declaration occurs for the given property and value
• getVendorPrefixed() function - returns an array of declarations with vendor prefixed properties
• getAllFontSizes() function - returns an array of font sizes from both font-size and font shorthand declarations
• getAllFontFamilies() function - returns an array of font families from both font-family and font shorthand declarations
• important array (optional) - !important declaration objects with property and value

• total number - total number of media queries
• unique number - total unique media queries
• values array - array of values for each media query
• contents array - array of media query blocks with full stats object for each

See the /test/results folder for example JSON results.

var cssstats = require('cssstats')
var stats = cssstats(css)

var specificityGraph = stats.selectors.getSpecificityGraph()

var sortedSelectors = stats.selectors.getSortedSpecificity()

var uniqueColorsCount = stats.declarations.getUniquePropertyCount('color')

var displayNoneCount = stats.declarations.getPropertyValueCount('display', 'none')

MIT

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request