webpack.config.js

var path = require('path');
var webpack = require("webpack");
module.exports = {
    mode: "production",

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

    resolve: {
        // Add '.ts' and '.tsx' as resolvable extensions.
        extensions: [".ts", ".tsx", ".js"],
        modules: ["client", "node_modules"]
    },

    module: {
        rules: [
            {
                test: /\.ts|\.tsx$/,
                exclude: /node_modules/,
                use: 'ts-loader'
            },
            // All output '.js' files will have any sourcemaps re-processed by 'source-map-loader'.
            {
                enforce: "pre",
                test: /\.js$/,
                loader: "source-map-loader"
            },
            {
                test: /\.s[ac]ss$/,
                use: [
                // Creates `style` nodes from JS strings
                'style-loader',
                // Translates CSS into CommonJS
                'css-loader',
                // Compiles Sass to CSS
                'sass-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"
    },
    devServer: {
        contentBase: path.join(__dirname, '/'),
        compress: true,
        port: 8080,
        historyApiFallback: {
            index: 'client/index.html'
        }
    },
    output: {
        publicPath: '/',
        filename:'bundle.js'
    },
    plugins: [
        new webpack.DefinePlugin({
            'process.env.IS_CLIENT': true,
        })
    ]
};