webpack.config.js

const HtmlWebPackPlugin = require('html-webpack-plugin');
const ExtractTextPlugin = require('extract-text-webpack-plugin');

module.exports = (env, argv) => {
  const isProduction = argv.mode === 'production';

  const extractSass = new ExtractTextPlugin({
    filename: '[name].css',
  });

  return {
    module: {
      rules: [
        {
          test: /\.[jt]sx?$/,
          exclude: /node_modules/,
          use: { loader: 'babel-loader' },
        },
        {
          test: /\.html$/,
          use: [
            {
              loader: 'html-loader',
              options: { minimize: true },
            },
          ],
        },
        {
          test: /\.s?css$/,
          use: extractSass.extract({
            use: [{ loader: 'css-loader' }, { loader: 'sass-loader' }],
            fallback: 'style-loader',
          }),
        },
      ],
    },
    resolve: {
      extensions: ['.js', '.jsx', '.ts', '.tsx'],
    },
    plugins: [
      new HtmlWebPackPlugin({
        template: './src/index.html',
        filename: './index.html',
      }),
      extractSass,
    ],

    devtool: isProduction ? 'source-map' : 'inline-source-map',
  };
};