webpack.config.js

let config = {
  entry: "./src/index.tsx",
  output: {
    filename: "bundle.js",
  },

  devServer: {
    progress: true
  },

  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: "ts-loader"
      },

      // All output '.js' files will have any sourcemaps re-processed by 'source-map-loader'.
      {
        enforce: "pre",
        test: /\.js$/,
        loader: "source-map-loader"
      },
      // All files with '.css' extension will be handled by 'style-loader' and 'css-loader'
      {
        test: /\.css$/,
        use: ['style-loader', 'css-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",
    "reactstrap": "Reactstrap",
    "cytoscape": "cytoscape",
    "redux": "Redux",
    "react-redux": "ReactRedux",
    "popper.js": "Popper",
    "cytoscape-popper": 'cytoscapePopper',
    "react-redux": "ReactRedux",
    "react-router-dom": "ReactRouterDOM",
    "cytoscape-svg": "cytoscapeSvg"
  }
};

module.exports = (env, argv) => {

  if (argv.mode === 'development') {
    config.output.path = __dirname + '/build';

  } else if (argv.mode === 'production') {
    config.output.path = __dirname + '/dist';
    const CompressionPlugin = require('compression-webpack-plugin')
    config.plugins = [new CompressionPlugin({
      test: /bundle\.js/,
      algorithm: 'gzip',
      compressionOptions: { level: 9 },
      deleteOriginalAssets: true,
    })]
  }

  return config;
};