Return the field name by which children are sorted
- If sort is descending, then field name is prepended with a "-".
- Returns the value "sort" if pages are unsorted or sorted manually.
- Note the return value from this method may be different from the
Page::sortfield(lowercase) property, as this method considers the sort field specified with the template as well.
$string = $page->sortfield();
API reference based on ProcessWire core version 3.0.130