webpack.config.js

module.exports = {
    mode: 'development',

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

    devServer: {
        writeToDisk: true
    },

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

    module: {
        rules: [
            {
                test: /\.ts(x?)$/,
                exclude: /node_modules/,
                use: [
                    {
                        loader: 'ts-loader'
                    }
                ]
            },
            {
                test: /\.s[ac]ss$/i,
                use: [
                  // Creates `style` nodes from JS strings
                  'style-loader',
                  // Translates CSS into CommonJS
                  'css-loader',
                  // Compiles Sass to CSS
                  'sass-loader',
                ],
            },
            // All output '.js' files will have any sourcemaps re-processed by 'source-map-loader'.
            {
                enforce: 'pre',
                test: /\.js$/,
                loader: 'source-map-loader'
            },
            {
                test: /\.svg$/,
                loader: 'svg-url-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'
    }
};