webpack.config.js

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

const isProduction = process.env.NODE_ENV == "production";

const stylesHandler = "style-loader";

const config = {
  entry: "./src/index.js",
  output: {
    path: path.join(__dirname, "/build"), // the bundle output path
  },
  devServer: {
    open: true,
    host: "localhost",
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: "public/index.html",
    }),

    // Add your plugins here
    // Learn more about plugins from https://webpack.js.org/configuration/plugins/
  ],
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/i,
        loader: "babel-loader",
      },
      {
        test: /\.css$/i,
        use: [stylesHandler, "css-loader"],
      },
      {
        test: /\.s[ac]ss$/i,
        use: [stylesHandler, "css-loader", "sass-loader"],
      },
      {
        test: /\.(eot|svg|ttf|woff|woff2|png|jpg|jpeg|gif)$/i,
        type: "asset",
      },

      // Add your rules for custom modules here
      // Learn more about loaders from https://webpack.js.org/loaders/
    ],
  },
};

module.exports = (env) => {
  if (isProduction) {
    config.mode = "production";
  } else {
    config.mode = "development";
  }

  if (env.library === "true") {
    delete config.plugins;
    delete config.devServer;

    config.entry = path.join(__dirname, "src", "App.js");
    config.output = {
      path: path.join(__dirname, "/lib"),
      filename: "index.js",
      globalObject: "this",
      library: {
        name: "BestSearch",
        type: "umd",
      },
    };

    config.externals = {
      // Don't bundle react or react-dom
      react: {
        root: "React",
        commonjs2: "react",
        commonjs: "react",
        amd: "react",
      },
      "react-dom": {
        root: "ReactDOM",
        commonjs2: "react-dom",
        commonjs: "react-dom",
        amd: "react-dom",
      },
    };
  }
  return config;
};