import {readFile, writeFile} from 'node:fs/promises'; import postcss from 'postcss'; import plugin from './../index.js'; readFile('from.css', { encoding: 'utf-8', }) .then((css) => { return postcss([ plugin({ blocks: ['.block-2'], }), ]).process(css, { from: 'from.css', }); }) .then(({css}) => { writeFile('to.css', css, { encoding: 'utf-8', }); });