webpack.config.js

const path = require('path');

module.exports = {
  entry: './src/index.tsx',
  output: {
    filename: 'bundle.js',
    path: path.resolve(__dirname, 'dist')
  },

  // Use 'production' for a minified version.
  mode: 'development',

  // Enable sourcemaps for debugging webpack's output.
  devtool: 'inline-source-map',

  resolve: {
    // Add '.ts' and '.tsx' as resolvable extensions.
    extensions: ['.ts', '.tsx', '.js', '.json']
  },

  module: {
    rules: [
      // All files with a '.ts' or '.tsx' extension will be handled by 'awesome-typescript-loader'.
      {
        test: /\.tsx?$/,
        loader: 'awesome-typescript-loader',
      },

      // All output '.js' files will have any sourcemaps re-processed by 'source-map-loader'.
      {
        enforce: 'pre',
        test: /\.js$/,
        loader: 'source-map-loader',
        exclude: [/node_modules/],
      },

      // Compile Scss
      {
        test: /\.scss$/,
        use: [
          "style-loader", // creates style nodes from JS strings
          "css-loader", // translates CSS into CommonJS
          "sass-loader" // compiles Sass to CSS
        ]
      }
    ]
  },

  // 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',
  },
};