I’ve got some form input fields in a paragraph whose visibility need to be dynamically toggled by the value of a another field. This can be done with the states API and the HOOK_field_widget_WIDGETTYPE_form_alter hook.

My problem is that the paragraph is nested inside another paragraph, and I don’t know how to get the delta of the parent widget, in order to build my selector name for the states API.

My node has a paragraph field_pagebuilder, which contains another paragraph field_row. All toggleable/dependant fields are inside the same sub-paragraph. This is the code I’ve got so far:

function wt_pricetable_field_widget_paragraphs_form_alter(&$element, DrupalCoreFormFormStateInterface $form_state, $context) {   if ($element['#paragraph_type'] == 'pricetable_frontend') {      $deltaSelf = $context['delta'];     //////////////////////////////     $deltaParent = 0; // FIXME: how to I get this?     //////////////////////////////     $element['subform']['field_pt_showroom']['#states'] = [       'visible' => [         [           'select[name="field_pagebuilder['.$deltaParent.'][subform][field_row]['.$deltaSelf.'][subform][field_pt_tablemode]"' => ['value' => 'single_room'],         ],       ],       'required' => [         [           'select[name="field_pagebuilder['.$deltaParent.'][subform][field_row]['.$deltaSelf.'][subform][field_pt_tablemode]"' => ['value' => 'single_room'],         ],       ],     ];     $element['subform']['field_pt_hiderooms']['#states'] = [       'visible' => [         [           'select[name="field_pagebuilder['.$deltaParent.'][subform][field_row]['.$deltaSelf.'][subform][field_pt_tablemode]"' => ['value' => 'multi_room'],         ],       ],       'required' => [         [           'select[name="field_pagebuilder['.$deltaParent.'][subform][field_row]['.$deltaSelf.'][subform][field_pt_tablemode]"' => ['value' => 'multi_room'],         ],       ],     ];     $element['subform']['field_bem_modifier']['#states'] = [       'visible' => [         [           'select[name="field_pagebuilder['.$deltaParent.'][subform][field_row]['.$deltaSelf.'][subform][field_pt_tablemode]"' => ['value' => 'multi_room'],         ],       ],       'required' => [         [           'select[name="field_pagebuilder['.$deltaParent.'][subform][field_row]['.$deltaSelf.'][subform][field_pt_tablemode]"' => ['value' => 'multi_room'],         ],       ],     ];   } } 

My problem is the $deltaParent – how can I retrive it?