webpack.config.js

const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const HtmlWebpackInlineSourcePlugin = require('html-webpack-inline-source-plugin');
const Critters = require('critters-webpack-plugin');

module.exports = {
  entry: __dirname + '/src/index.js',

  output: {
    path: __dirname,
    filename: 'bundle.js'
  },

  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['env']
          }
        }
      },
      {
        test: /\.css$/,
        use: ['style-loader', 'css-loader']
      }
    ]
  },

  plugins: [
    new HtmlWebpackPlugin({
      template: './src/template.html',
      filename: './index.html',
      inlineSource: '.(js|css)$',
      minify: {
        collapseWhitespace: true,
        removeComments: true,
        removeRedundantAttributes: true,
        removeScriptTypeAttributes: true,
        useShortDoctype: true,
      }
    }),
    new HtmlWebpackInlineSourcePlugin(),
    new Critters({
      preload: 'body',
    }),
  ]
}