slt_contacts.module

<?php

/**
 * @file
 * Code for the SLT contacts module.
 */

use Drupal\Core\Form\FormStateInterface;

/**
 * Implements hook_form_FORM_ID_alter().
 *
 * Change default value for the exposed country selector.
 */
function slt_contacts_form_views_exposed_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  $view = $form_state->getStorage('view');
  if (isset($view['view']) && $view['view']->id() === 'contacts' && $view['view']->current_display === 'page_contacts') {
    // We re-use the 'All' option to avoid validation errors and add a process
    // function to actually remove the filter when 'All' is selected.
    $form['country']['#options']['All'] = t('- Choose a country -');
    $form['country']['#process'][] = 'slt_contacts_reset_country_default_filter';
  }
}

/**
 * Process function for the exposed country filter in the contacts view.
 *
 * This ensures that no data is returned with "Choose a country" is the
 * currently selected option.
 *
 * @param array $element
 *   Form element to process.
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 *   Form state.
 *
 * @return array
 *   Processed element.
 *
 * @see \Drupal\views\ViewExecutable::getExposedInput()
 */
function slt_contacts_reset_country_default_filter(array $element, FormStateInterface $form_state) {
  $view = $form_state->getStorage('view');
  if (isset($view['view']) && $form_state->getValue('country') === 'All') {
    $input = $view['view']->getExposedInput();
    unset($input['country']);

    // We set a dummy input value to ensure ViewExecutable::getExposedInput()
    // doesn't bail out due to an empty input which would counteract the
    // removal of the 'country' filter value and would cause the query to
    // return all the entries as if 'All' were still selected.
    $input['__dummy'] = 'Dummy input';
    $view['view']->setExposedInput($input);
  }
  return $element;
}

/**
 * Implements hook_views_data_alter().
 *
 * Change the sort handler for the seurity title field so that they can
 * be sorted according to a predefined order (title hierarchy) [SLT-14].
 */
function slt_contacts_views_data_alter(array &$data) {
  $data['node__field_security_title']['hierarchical_security_title_sort'] = [
    'title' => t('Hierarchical security title sort'),
    'group' => t('Content'),
    'help' => t('Sort contacts by security title hierarchically.'),
    'sort' => [
      'field' => 'field_security_title_value',
      'id' => 'hierarchical_security_title_sort',
    ],
  ];
}