postcss-rtl/src/keyframes.js

PostCSS plugin for RTL-optimizations

function unprefixed(prop) {
  return prop.replace(/^-\w+-/, '');
}

const {rtlifyDecl} = require('./decls');
const {rtlifyRule} = require('./rules');

const isKeyframeRule = (rule) => rule.type === 'atrule' && unprefixed(rule.name) === 'keyframes';

const isKeyframeAlreadyProcessed = (rule) => !!rule.params.match(/-ltr$|-rtl$/);

const isKeyframeSymmetric = (rule) => !rtlifyRule(rule);

const rtlifyKeyframe = (rule, options) => {
  const ruleName = rule.params;

  rule.params = `${ruleName}-ltr`;

  if (!options.onlyDirection || options.onlyDirection === 'rtl') {
    const rtlRule = rule.cloneAfter({params: `${ruleName}-rtl`});

    rtlRule.walkDecls((decl) => {
      const rtl = rtlifyDecl(decl);
      decl.value = rtl ? rtl.value : decl.value;
    });
  }

  if (options.onlyDirection && options.onlyDirection === 'rtl') {
    rule.remove();
  }
};

module.exports = {
  isKeyframeRule,
  isKeyframeAlreadyProcessed,
  isKeyframeSymmetric,
  rtlifyKeyframe,
};