webpack.config.js

var path = require("path");
const TerserPlugin = require("terser-webpack-plugin");

const isProduction = process.env.NODE_ENV;

module.exports = {
  mode: !!isProduction ? "production" : "development",
  entry: "./components/index.js",
  output: {
    path: path.resolve("lib"),
    filename: "index.js",
    libraryTarget: "commonjs2",
  },
  resolve: {
    extensions: [".js", ".jsx", ".ts", ".tsx"],
  },
  module: {
    rules: [
      {
        test: /\.js?$/,
        exclude: /(node_modules)/,
        use: "babel-loader",
      },
      {
        test: /\.(tsx|ts)?$/,
        use: "ts-loader",
        exclude: /node_modules/,
      },
      {
        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",
        ],
      },
    ],
  },
  externals: {
    react: {
      root: "React",
      commonjs2: "react",
      commonjs: "react",
      amd: "react",
    },
    "react-dom": {
      root: "ReactDOM",
      commonjs2: "react-dom",
      commonjs: "react-dom",
      amd: "react-dom",
    },
  },
  optimization: !!isProduction
    ? { minimize: true, minimizer: [new TerserPlugin()] }
    : {},
};