ash_admin/assets/webpack.config.js

const path = require('path');
const glob = require('glob');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const TerserPlugin = require('terser-webpack-plugin');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');

module.exports = (env, options) => ({
  optimization: {
    minimizer: [
      new TerserPlugin({ cache: true, parallel: true, sourceMap: false }),
      new OptimizeCSSAssetsPlugin({})
    ]
  },
  entry: {
    './js/app.js': glob.sync('./vendor/**/*.js').concat(['./js/app.js'])
  },
  output: {
    filename: 'app.js',
    path: path.resolve(__dirname, '../priv/static/js')
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader'
        }
      },
      {
        test: /\.css$/,
        use: [
          MiniCssExtractPlugin.loader,
          { loader: 'css-loader' }
        ]
      },
      {
        test: /\.scss$/,
        use: [MiniCssExtractPlugin.loader,
        {
          loader: 'css-loader',
        }, {
          loader: 'postcss-loader',
          options: {
            plugins: function () {
              return [
                require('precss'),
                require('autoprefixer'),
                require('tailwindcss')
              ];
            }
          }
        }, {
          loader: 'sass-loader'
        }]
      },
      {
        test: /\.(woff2)$/,
        loader: 'url-loader'
      },
    ]
  },
  plugins: [
    new MiniCssExtractPlugin({ filename: '../css/app.css' })
  ]
});