code: private function getTransformation()
      {
          $transforms = [];
          foreach ($this->fields as $field => $extra) {
              if (is_int($field)) {
                  $transforms[$extra] = $extra;
                  continue;
              }
              
              $transform = (key_exists('transform', $extra)) ? $extra['transform'] : $field;
              
              if ($transform === false) {
                  continue;
              }
              
              $transforms[$field] = $transform;
          }
          
          return $transforms;
      }
docs: Get the transformation data
  
  @return array