webpack.config.js

const path = require('path');
module.exports = {
  entry: './src/index.tsx',
  module: {
    rules: [
      // changed from { test: /\.jsx?$/, use: { loader: 'babel-loader' }, exclude: /node_modules/ },
      {
        test: /\.(t|j)sx?$/,
        use: {
          loader: 'ts-loader'
        },
        exclude: /node_modules/
      },

      // addition - add source-map support
      {
        enforce: "pre",
        test: /\.js$/,
        exclude: /node_modules/,
        loader: "source-map-loader"
      },
      {
        test: /\.css$/,
        use: ["style-loader", "css-loader"]
      },
      {
        test: /\.(png|jpe?g|gif)$/i,
        use: [
          {
            loader: 'file-loader',
          },
        ],
      },
    ]
  },
  resolve: {
    extensions: ['.tsx', '.ts', '.js', '.jsx'],
  },
  externals: {
    "react": "React",
    "react-dom": "ReactDOM",
  },
  // addition - add source-map support
  devtool: "source-map",
  output: {
    filename: 'bundle.js',
    path: path.resolve(__dirname, 'dist'),
  },
};