code: function makeWebpackExternalsConfig(moduleNames) {
    return moduleNames.reduce((externals, moduleName) => Object.assign(externals, {
      [moduleName]: `commonjs ${moduleName}`,
    }), {});
  }
docs: Make a webpack 'externals' object from the provided CommonJS module names.
  @param  {Array<String>} moduleNames The list of module names
  @return {Object}                    A webpack 'externals' config object