webpack.config.babel.js

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

const entries = {
  admin: ['regenerator-runtime', path.join(__dirname, 'typescript/admin.ts')],
  frontend: [
    'regenerator-runtime',
    path.join(__dirname, 'typescript/frontend.ts'),
  ],
}

const minifiedEntries = {
  'admin.min': [
    'regenerator-runtime',
    path.join(__dirname, 'typescript/admin.ts'),
  ],
  'frontend.min': [
    'regenerator-runtime',
    path.join(__dirname, 'typescript/frontend.ts'),
  ],
}

export default ({ NODE_ENV: env }) => ({
  mode: env,
  entry: {
    ...entries,
    ...(env === 'production' ? minifiedEntries : {}), // Generate additional entries in prod only
  },
  output: {
    path: path.resolve(__dirname, './dist'),
    filename: '[name].js',
    libraryTarget: 'umd',
    globalObject: 'this',
    libraryExport: 'default',
    library: 'myEmptyPlugin',
  },
  resolve: {
    extensions: ['.mjs', '.ts', '.tsx', '.js'],
    // uncomment if enabling webpack-dev-server
    // alias:
    //   env === "development"
    //     ? {
    //         "react-dom": "@hot-loader/react-dom",
    //       }
    //     : {},
  },
  externals: {
    // Any libraries provided by WordPress should be excluded from the bundle.
    // react: 'React',
    // 'react-dom': 'ReactDOM',

    react: {
      commonjs: 'react',
      commonjs2: 'react',
      amd: 'React',
      root: 'React',
    },
    'react-dom': {
      commonjs: 'react-dom',
      commonjs2: 'react-dom',
      amd: 'ReactDOM',
      root: 'ReactDOM',
    },
  },
  optimization:
    env === 'production'
      ? {
          minimizer: [
            new TerserJSPlugin({
              test: /\.min\.m?js(\?.*)?$/i,
            }),
            new OptimizeCSSAssetsPlugin({
              assetNameRegExp: /\.min\.css$/g,
            }),
          ],
        }
      : {},
  plugins: [
    new MiniCssExtractPlugin({
      // Options similar to the same options in webpackOptions.output
      // both options are optional
      filename: '[name].css',
      chunkFilename: '[id].css',
    }),
  ],
  // stats: 'errors-warnings',
  devtool: env !== 'production' ? 'inline-source-map' : false,
  module: {
    rules: [
      {
        test: /\.(png|jpe?g|gif|svg)$/i,
        use: [
          {
            loader: 'file-loader',
          },
        ],
      },

      {
        test: /\.(js)x?$/,
        exclude: /(node_modules)/,
        use: 'babel-loader',
      },

      {
        test: /\.(ts)x?$/,
        exclude: /node_modules/,
        use: [
          {
            loader: 'babel-loader',
          },

          {
            loader: 'ts-loader',
          },
        ],
      },

      { test: /\.(woff|woff2|eot|ttf)$/, loader: 'url-loader' },

      {
        test: /\.(scss|css)$/,
        use: [
          {
            loader: MiniCssExtractPlugin.loader,
            options: {
              // you can specify a publicPath here
              // by default it uses publicPath in webpackOptions.output
              publicPath: '../',
              hmr: process.env.NODE_ENV === 'development',
            },
          },
          'css-loader', // translates CSS into CommonJS
          'postcss-loader', // autoprefixer etc
          'sass-loader', // compiles Sass to CSS, using Node Sass by default
        ],
      },
    ],
  },
})