webpack.config.js

const path = require("path");
const HtmlWebpackPlugin = require("html-webpack-plugin");

module.exports = {
  entry: path.join(__dirname, "src", "index.js"),
  output: {
    path: path.resolve(__dirname, "dist"),
  },
  externals: {
    // Use external version of React
    react: {
      commonjs: "react",
      commonjs2: "react",
      amd: "react",
      root: "React",
    },
    "react-dom": {
      commonjs: "react-dom",
      commonjs2: "react-dom",
      amd: "react-dom",
      root: "ReactDOM",
    },
  },
  module: {
    rules: [
      {
        enforce: "pre",
        test: /\.?js$/,
        loader: "source-map-loader",

        exclude: /node_modules/,
        use: {
          loader: "babel-loader",
          options: {
            presets: ["@babel/preset-env", "@babel/preset-react"],
          },
        },
      },
    ],
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: path.join(__dirname, "src", "index.html"),
    }),
  ],
  resolve: [
    {
      react: path.resolve("./node_modules/react"),
    },
  ],
};