/**
* Determine the local path of a cache file.
*
- * @param string|NULL $fileName
+ * @param string|null $fileName
* Ex: 'angular.abcd1234abcd1234.json'.
* @return string
* URL.
/**
* Determine the URL of a cache file.
*
- * @param string|NULL $fileName
+ * @param string|null $fileName
* Ex: 'angular.abcd1234abcd1234.json'.
* @return string
* URL.