icon_select_field.module

<?php

/**
 * @file
 * Contains icon_select_field.module..
 */

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Render\Element;
use Drupal\Core\Render\Element\RenderElement;

/**
 * Implements hook_help().
 */
function icon_select_field_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the icon_select_field module.
    case 'help.page.icon_select_field':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Use jQuery plugin Select2 dropdown to select an icon from a given list. See the settings page to enter some values') . '</p>';
      return $output;

    default:
  }
}

/**
 * Implements hook_theme().
 */
function icon_select_field_theme() {
  return [
    'icon_select_select' => [
      'render element' => 'element',
      'template' => 'icon-select-select',
      'base hook' => 'select',
    ],
  ];
}

/**
 * Implements hook_page_attachments().
 *
 * Add library to the edit node page.
 * Fields may be loaded lazy resulting in missing library, if only defined in
 * twig template.
 *
 * @see contextual_preprocess()
 */
function icon_select_field_page_attachments(array &$page) {
  if (!\Drupal::currentUser()->isAuthenticated()) {
    return;
  }

  $page['#attached']['library'][] = 'icon_select_field/select';
}

/**
 * Prepares variables for select element templates.
 *
 * Default template: select.html.twig.
 *
 * It is possible to group options together; to do this, change the format of
 * $options to an associative array in which the keys are group labels, and the
 * values are associative arrays in the normal $options format.
 *
 * @param $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #title, #value, #options, #description, #extra,
 *     #multiple, #required, #name, #attributes, #size.
 */
function icon_select_field_preprocess_icon_select_select(&$variables) {
  $element = $variables['element'];

  Element::setAttributes($element, ['id', 'name', 'size']);
  RenderElement::setAttributes($element, ['form-select']);

  $variables['icon_select_tag_list'] = $element['#icon_select_tag_list'];
  $variables['attributes'] = $element['#attributes'];
  $variables['options'] = form_select_options($element);
}