postcss-merge-longhand/src/lib/minifyTrbl.js

Merge longhand properties into shorthand with PostCSS.

import parseTrbl from './parseTrbl.js';

/**
 * @param {string | string[]} v
 * @return {string}
 */
export default (v) => {
  const value = parseTrbl(v);

  if (value[3] === value[1]) {
    value.pop();

    if (value[2] === value[0]) {
      value.pop();

      if (value[0] === value[1]) {
        value.pop();
      }
    }
  }

  return value.join(' ');
};