code: protected function getSortColumn($field, Model $model)
      {
          /** If there is a custom mapping, return that */
          if (isset($this->sortColumns[$field])) {
              return $this->sortColumns[$field];
          }
  
          return $model::$snakeAttributes ? Str::underscore($field) : Str::camelize($field);
      }
docs: Get the table column to use for the specified search field.
  
  @param string $field
  @param Model $model
  @return string