webpack.config.js

const path =  require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = {
  mode: 'development',

  entry: {
    index: ['./src/index.tsx'],
  },

  output: {
    path: path.resolve(__dirname, 'dist'),
    filename: 'index_bundle.js',
    publicPath: '/'
  },

  plugins: [
    new HtmlWebpackPlugin({
      template: './src/index.html'
    }),
    new MiniCssExtractPlugin({
      filename: '[name].css'
    })
  ],

  devtool: 'source-map',

  resolve: { extensions: ['.tsx', '.js', '.css', '.scss'] },

  module: {
    rules: [
      {
        test: /\.ts(x?)$/,
        exclude: /node_modules/,
        loader: 'ts-loader'
      },
      {
        enforce: 'pre',
        test: /\.js$/,
        loader: 'source-map-loader'
      },
      {
        test: /\.scss$/, 
        use: [
          { loader: MiniCssExtractPlugin.loader},
          { loader: 'css-modules-typescript-loader'},
          { 
            loader: 'css-loader', 
            options: {
              modules: {
                localIdentName: '[name]__[local]--[hash:base64:5]'
              }
            }
          },
          { loader: 'sass-loader' },
          { loader: 'postcss-loader'}
        ]
      }
    ]
  },

  // When importing a module whose path matches one of the following, just
  // assume a corresponding global variable exists and use that instead.
  // This is important because it allows us to avoid bundling all of our
  // dependencies, which allows browsers to cache those libraries between builds.
  externals: {
    'react': 'React',
    'react-dom': 'ReactDOM'
  }
};