webpack.config.js

const path = require('path');

module.exports = buildJSFiles([
  'BookReader.js',
  'plugins/menu_toggle/plugin.menu_toggle.js',
  'plugins/plugin.archive_analytics.js',
  'plugins/plugin.autoplay.js',
  'plugins/plugin.chapters.js',
  'plugins/plugin.iframe.js',
  'plugins/plugin.mobile_nav.js',
  'plugins/plugin.print.js',
  'plugins/plugin.resume.js',
  'plugins/plugin.search.js',
  'plugins/plugin.themes.js',
  'plugins/plugin.url.js',
  'plugins/plugin.vendor-fullscreen.js',
  'plugins/tts/plugin.tts.js',
]);

/**
 * Applies bundling to the listed files.
 */
function buildJSFiles(files) {
  const nestedDirRegex = new RegExp('/(.*)/');
  return files.map((filePath) => {
    const flattenedFilePath = filePath.replace(nestedDirRegex, '/');
    return buildJsFromTo({
      from: filePath,
      to: `BookReader/${flattenedFilePath}`
    });
  });
}

/**
 * Applies webpack config to files that it is bundling.
 *
 * @param {Object} opts
 * @param {String} opts.from
 * @param {String} opts.to
 */
function buildJsFromTo({ from: srcEntryFile, to: outputFile }) {
  return {
    mode: 'production',
    entry: './' + path.join('src/js/', srcEntryFile),
    module: {
      rules: [
        { test: /\.js$/, exclude: /node_modules/, loader: "babel-loader" }
      ]
    },

    output: {
      filename: path.basename(outputFile),
      path: path.resolve(__dirname, path.parse(outputFile).dir)
    },

    // Accurate source maps at the expense of build time.
    // The source map is intentionally exposed
    // to users via sourceMapFilename for prod debugging.
    devtool: 'source-map'
  };
}