code: public function hasQueryVar($key)
      {
          if (!$this->hasQuery()) {
              return false;
          }
  
          parse_str($this->query, $queryArray);
  
          return array_key_exists($key, $queryArray) ? true : false;
      }
docs: Returns TRUE if the URI has a query variable.
  
  @param $key
  @return boolean