My config for Laravel Mix with PurgeCSS.

gistfile1.txt

let mix = require('laravel-mix');
let glob = require('glob-all');
let PurgecssPlugin = require('purgecss-webpack-plugin');

/*
 |--------------------------------------------------------------------------
 | Mix Asset Management
 |--------------------------------------------------------------------------
 |
 | Mix provides a clean, fluent API for defining some Webpack build steps
 | for your Laravel application. By default, we are compiling the Sass
 | file for your application, as well as bundling up your JS files.
 |
 */

mix.setPublicPath('static');
mix.options({ processCssUrls: false });

mix.webpackConfig({
  plugins: [
    new PurgecssPlugin({
      paths: glob.sync([
        path.join(__dirname, "templates/**/*.twig"),
        path.join(__dirname, "resources/scripts/**/*.vue")
      ])
    })
  ]
});

mix.copy('resources/images', 'static/images');
mix.copy('resources/fonts', 'static/fonts');

mix.js('resources/scripts/app.js', 'app.js');
mix.sass('resources/styles/app.scss', 'app.css');

mix.version();