const { PurgeCSS } = require('purgecss') var fs = require('fs'); async function purgeBuild() { const purgeCSSResult = await new PurgeCSS().purge({ content: ['../src/**/*.js', '../src/**/*.jsx',], css: ['../public/css/edu-public.css', '../public/css/taskstyle.css', '../public/css/edu-main.css', '../public/css/edu-all.css'] }) let result = [] for (let i = 0; i < purgeCSSResult.length; i++) { let item = purgeCSSResult[i] result.push(item.css) } fs.writeFile('../public/css/edu-purge.css', result.join(''), 'utf8', function (err) { if (err) return console.log(err) }) } purgeBuild()