site/themes/minimo/webpack.config.js

const path = require('path')
const autoprefixer = require('autoprefixer')
const cssnano = require('cssnano')
const AssetsWebpackPlugin = require('assets-webpack-plugin')
const { CleanWebpackPlugin } = require('clean-webpack-plugin')
const MiniCSSExtractPlugin = require('mini-css-extract-plugin')

const assetsManifest = new AssetsWebpackPlugin({
  filename: 'assets.json',
  path: path.join(__dirname, 'data'),
  fullPath: false,
  processOutput: assets => {
    Object.keys(assets).forEach(bundle => {
      Object.keys(assets[bundle]).forEach(type => {
        let filename = assets[bundle][type]
        assets[bundle][type] = filename.slice(filename.indexOf(bundle))
      })
    })
    return JSON.stringify(assets, null, 2)
  }
})

const extractCSS = new MiniCSSExtractPlugin({
  filename: '../css/[name].[contenthash:8].css'
})

const cleanBuild = new CleanWebpackPlugin({
  cleanOnceBeforeBuildPatterns: [
    path.resolve('static/assets/css/*'),
    path.resolve('static/assets/js/*')
  ]
})

const node_env = process.env.NODE_ENV

const config = {
  mode: node_env === 'production' ? 'production' : 'development',
  entry: {
    main: path.join(__dirname, 'src/scripts', 'main.js'),
    algolia_search: path.join(__dirname, 'src/scripts/search', 'algolia.js'),
    fuse_search: path.join(__dirname, 'src/scripts/search', 'fuse.js'),
    lunr_search: path.join(__dirname, 'src/scripts/search', 'lunr.js'),
    rtl: path.join(__dirname, 'src/stylesheets', 'rtl.scss')
  },
  output: {
    filename: '[name].[chunkhash:8].js',
    chunkFilename: '[name].[chunkhash:8].js',
    path: path.join(__dirname, 'static', 'assets/js')
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        include: path.join(__dirname, 'src/scripts'),
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env'],
            plugins: ['@babel/plugin-syntax-dynamic-import']
          }
        }
      },
      {
        test: /\.scss$/,
        include: [path.resolve(__dirname, 'src/stylesheets')],
        use: [
          MiniCSSExtractPlugin.loader,
          {
            loader: 'css-loader',
            options: {
              importLoaders: 1
            }
          },
          {
            loader: 'postcss-loader',
            options: {
              plugins: [
                autoprefixer(),
                'production' === node_env
                  ? cssnano({
                      preset: [
                        'default',
                        { discardComments: { removeAllButFirst: true } }
                      ]
                    })
                  : null
              ].filter(Boolean)
            }
          },
          'sass-loader'
        ]
      }
    ]
  },
  resolve: {
    extensions: ['*', '.js', '.scss']
  },
  plugins: [extractCSS, assetsManifest]
}

if (node_env === 'production') config.plugins.push(cleanBuild)

module.exports = config