```js
// .storybook/main.js

export function webpackFinal(config, { configDir }) {
  if (!isReactScriptsInstalled()) {
    logger.info('=> Using base config because react-scripts is not installed.');
    return config;
  }

  logger.info('=> Loading create-react-app config.');
  return applyCRAWebpackConfig(config, configDir);
}
```