code: public function isActiveMatch($string, $output = "active")
      {
          if (strpos($this->url->current(), $string) !== false) {
              return $output;
          }
  
          return null;
      }
docs: Detects if the given string is found in the current URL.
  
  @param  string  $string
  @param  string  $output
  @return boolean