rollup-plugin-purifycss 
Seamless integration between Rollup and PurifyCSS.
$ npm i rollup-plugin-purifycss -D
# or
$ yarn add rollup-plugin-purifycss -D
import { join } from 'path';
import purifycss from 'rollup-plugin-purifycss';
export default {
input: join(__dirname, 'main.js'),
output: [{ file: join(__dirname, 'bundle.js'), format: 'iife' }],
plugins: [
purifycss({
content: ['./**/*.js', './**/*.html'],
options: {
info: true,
},
}),
],
};
