entity_reference_hierarchy.module

<?php

use Drupal\Core\Render\Element;

/**
 * Implements hook_field_info_alter().
 *
 * This removes "entity_reference_revisions_hierarchy" field type plugin
 * if "entity_reference_revisions" module is not enabled.
 */
function entity_reference_hierarchy_field_info_alter(&$info) {
  if (isset($info['entity_reference_revisions_hierarchy']) && !\Drupal::moduleHandler()->moduleExists('entity_reference_revisions')) {
    unset($info['entity_reference_revisions_hierarchy']);
  }
}

/**
 * Implements hook_field_formatter_info_alter().
 *
 * This enables "entity_reference" field formatters be applied to
 * "entity_reference_hierarchy" and "entity_reference_revisions_hierarchy"
 * field types.
 */
function entity_reference_hierarchy_field_formatter_info_alter(array &$info) {
  foreach ($info as &$info_item) {
    if (isset($info_item['field_types'])) {
      if (in_array('entity_reference', $info_item['field_types'])) {
        $info_item['field_types'][] = 'entity_reference_hierarchy';
        $info_item['field_types'][] = 'entity_reference_revisions_hierarchy';
      }
      else if (in_array('entity_reference_revisions', $info_item['field_types'])) {
        $info_item['field_types'][] = 'entity_reference_revisions_hierarchy';
      }
    }
  }
}

/**
 * Pre-processor for "field_multiple_value_form" theme.
 *
 * Applies only to widgets of field type "entity_reference_hierarchy".
 *
 * @param $variables
 */
function entity_reference_hierarchy_preprocess_field_multiple_value_form(&$variables) {
  $element = $variables['element'];

  if (!empty($element['#entity_reference_hierarchy'])) {
    $table = &$variables['table'];
    // Remove colspan on the field header cell.
    $table['#header'][0]['colspan'] -= 1;
    // Remove the weight header cell.
    unset($table['#header'][1]);

    foreach (Element::children($variables['element']) as $key) {
      if (is_numeric($key)) {
        // Remove the first column (drag handle).
        unset($table['#rows'][$key]['data'][0]);
        // Remove the weight column.
        unset($table['#rows'][$key]['data'][2]);
        // Prepare indentation.
        $indentation = [
          '#theme' => 'indentation',
          '#size' => $variables['element'][$key]['depth']['#value'],
        ];
        // Inject indentation into the content cell.
        array_unshift($table['#rows'][$key]['data'][1]['data'], $indentation);
      }
    }

    // Replace tabledrag options.
    $table['#tabledrag'] = [
      [
        'action' => 'match',
        'relationship' => 'parent',
        'group' => 'item-parent',
        'subgroup' => 'item-parent',
        'source' => 'item-index',
        'hidden' => FALSE,
      ],
      [
        'action' => 'depth',
        'relationship' => 'group',
        'group' => 'item-depth',
        'hidden' => FALSE,
      ],
    ];
  }
}