stylelint-sustainable-css/lib/rules/avoid-duplicate-media-queries/index.js

Sustainable CSS is a Stylelint plugin dedicated to following sustainable web design principles.

const stylelint = require('stylelint');

const ruleName = 'sustainable-css/avoid-duplicate-media-queries';

function avoidDuplicateMediaQueries() {
  return (root, result) => {
    const mediaQueries = {};
    root.walkAtRules('media', atRule => {

      const params = atRule.params;

      if (!mediaQueries[params]) {
        mediaQueries[params] = [];
      }

      atRule.walkRules(rule => {
        mediaQueries[params].push(rule.selector);
      });
    });

    Object.keys(mediaQueries).forEach(params => {
      if (mediaQueries[params].length > 1) {
        stylelint.utils.report({
          message: "Combine similar media queries to optimize stylesheet size",
          node: root,
          result,
          ruleName,
          severity: 'warning',
        });
      }
    });
  };
}

module.exports = avoidDuplicateMediaQueries;