webpack.config.js

const path = require("path");
const Dotenv = require("dotenv-webpack");
module.exports = {
  mode: "production",
  entry: "./src/EmailEditor.js",
  output: {
    path: path.resolve("lib"),
    filename: "EmailEditor.js",
    libraryTarget: "commonjs2",
  },
  plugins: [
    new Dotenv({
      path: "./editor.env",
      safe: true,
      allowEmptyValues: true,
      systemvars: true,
      silent: true,
      defaults: false,
    }),
  ],
  module: {
    rules: [
      {
        test: /\.js?$/,
        exclude: /(node_modules)/,
        use: "babel-loader",
      },
      {
        test: /\.css$/,
        use: ["style-loader", "css-loader"],
      },
    ],
  },
  resolve: {
    alias: {
      react: path.resolve(__dirname, "./node_modules/react"),
      "react-dom": path.resolve(__dirname, "./node_modules/react-dom"),
    },
  },
  externals: {
    // Don't bundle react or react-dom
    react: {
      commonjs: "react",
      commonjs2: "react",
      amd: "React",
      root: "React",
    },
    "react-dom": {
      commonjs: "react-dom",
      commonjs2: "react-dom",
      amd: "ReactDOM",
      root: "ReactDOM",
    },
  },
};