code: private function isEmptyComment($content)
      {
          static $mapper = [
              self::TYPE_HASH => '|^#\s*$|', // single line comment starting with '#'
              self::TYPE_SLASH_ASTERISK => '|^/\*\s*\*/$|', // comment starting with '/*' and ending with '*/' (but not a PHPDoc)
              self::TYPE_DOUBLE_SLASH => '|^//\s*$|', // single line comment starting with '//'
          ];
  
          $type = $this->getCommentType($content);
  
          return 1 === Preg::match($mapper[$type], $content);
      }
docs: @param string $content
  
  @return bool