import cssnano from 'cssnano'; import path from 'path'; import fs from 'fs'; const files = fs.readdirSync(path.resolve('lib/themes')); files.forEach(file => { file = path.resolve('lib/themes', file); cssnano .process(fs.readFileSync(file)) .then(result => { fs.writeFileSync(file, result.css); }) .catch(e => { console.error(e); process.exit(1); }); });