v1/web/themes/contrib/gin/includes/form.theme

<?php

/**
 * @file
 * form.theme
 */

use Drupal\Core\Form\FormStateInterface;
use Drupal\gin\GinDescriptionToggle;
use Drupal\gin\GinPreRender;
use Drupal\gin\GinContentFormHelper;
use Drupal\gin\GinSettings;

/**
 * Implements form_alter_HOOK() for some major form changes.
 */
function gin_form_alter(&$form, $form_state, $form_id) {
  \Drupal::classResolver(GinContentFormHelper::class)->formAlter($form, $form_state, $form_id);

  // User form (Login, Register or Forgot password).
  if (strpos($form_id, 'user_login') !== FALSE || strpos($form_id, 'user_register') !== FALSE || strpos($form_id, 'user_pass') !== FALSE) {
    $form['actions']['submit']['#attributes']['class'][] = 'button--primary';
  }

  // Bulk forms: update action & actions to small variants.
  if (strpos($form_id, 'views_form') !== FALSE) {
    if (isset($form['header'])) {
      $bulk_form = current(preg_grep('/_bulk_form/', array_keys($form['header'])));

      if (isset($form['header'][$bulk_form])) {
        $form['header'][$bulk_form]['action']['#attributes']['class'][] = 'form-element--type-select--small';
        $form['header'][$bulk_form]['actions']['submit']['#attributes']['class'][] = 'button--small';

        // Remove double entry of submit button.
        unset($form['actions']['submit']);
      }
    }
  }

  // Delete forms: alter buttons.
  if (strpos($form_id, 'delete_form') !== FALSE) {
    $form['actions']['submit']['#attributes']['class'][] = 'button--danger';
    $form['actions']['cancel']['#attributes']['class'][] = 'button--secondary';
  }
}

/**
 * Implements form_user_form_alter().
 */
function gin_form_user_form_alter(&$form, FormStateInterface $form_state) {
  // If new user account, don't show settings yet.
  if ($form_state->getFormObject()->getEntity()->isNew()) {
    return;
  }

  /** @var \Drupal\gin\GinSettings $settings */
  $settings = \Drupal::classResolver(GinSettings::class);

  if ($settings->allowUserOverrides()) {
    // Inject the settings for the dark mode feature.
    $form['gin_theme_settings'] = [
      '#type' => 'details',
      '#title' => t('Admin theme settings'),
      '#open' => TRUE,
      '#weight' => 90,
    ];

    /** @var \Drupal\Core\Session\AccountInterface $account */
    $account = $form_state->getBuildInfo()['callback_object']->getEntity();
    $form['gin_theme_settings']['enable_user_settings'] = [
      '#type' => 'checkbox',
      '#title' => t('Enable overrides'),
      '#description' => t("Enables default admin theme overrides."),
      '#default_value' => $settings->userOverrideEnabled($account),
      '#weight' => 0,
    ];

    $form['gin_theme_settings']['user_settings'] = [
      '#type' => 'container',
      '#states' => [
        // Show if met.
        'visible' => [
          ':input[name="enable_user_settings"]' => ['checked' => TRUE],
        ],
      ],
    ] + $settings->getSettingsForm($account);

    // Attach custom library.
    $form['#attached']['library'][] = 'gin/settings';

    array_unshift($form['actions']['submit']['#submit'], '_gin_user_form_submit');
  }
}

/**
 * Implements template_preprocess_HOOK() for select.
 */
function gin_preprocess_select(&$variables) {
  if (in_array('block-weight', $variables['attributes']['class'], TRUE)) {
    $variables['attributes']['class'][] = 'form-element--extrasmall';
  }
}

/**
 * Implements form_alter() for forms.
 */
function gin_theme_suggestions_form_alter(array &$suggestions, array $variables) {
  $suggestions[] = 'form__' . str_replace('-', '_', $variables['element']['#id']);
}

/**
 * Implements form_alter() for input.
 */
function gin_theme_suggestions_input_alter(array &$suggestions, array $variables) {
  if ($variables['element']['#type'] === 'checkbox') {
    // Way to identify if checkbox is in a checkboxes group
    // as Drupal doesn't provide one yet (see #2643012)
    if (!isset($variables['element']['#error_no_message'])) {
      $suggestions[] = 'input__checkbox__toggle';
    }
  }
}

/**
 * Implements template_preprocess_HOOK() for form_element.
 */
function gin_preprocess_form_element(&$variables) {
  \Drupal::classResolver(GinDescriptionToggle::class)->preprocess($variables);
}

/**
 * Implements template_preprocess_HOOK() for datetime_wrapper.
 */
function gin_preprocess_datetime_wrapper(&$variables) {
  \Drupal::classResolver(GinDescriptionToggle::class)->preprocess($variables);
}

/**
 * Implements template_preprocess_HOOK() for details.
 */
function gin_preprocess_details(&$variables) {
  \Drupal::classResolver(GinDescriptionToggle::class)->preprocess($variables);
}

/**
 * Implements template_preprocess_HOOK() for fieldset.
 */
function gin_preprocess_fieldset(&$variables) {
  \Drupal::classResolver(GinDescriptionToggle::class)->preprocess($variables);
}

/**
 * Implements hook_element_info_alter().
 */
function gin_element_info_alter(&$info) {
  if (array_key_exists('text_format', $info)) {
    $info['text_format']['#pre_render'][] = [
      GinPreRender::class,
      'textFormat',
    ];
  }
}

/**
 * Implements template_preprocess_HOOK() for text_format_wrapper.
 */
function gin_preprocess_text_format_wrapper(&$variables) {
  /** @var \Drupal\gin\GinSettings $settings */
  $settings = \Drupal::classResolver(GinSettings::class);
  if ($settings->get('show_description_toggle') && !empty($variables['description'])) {
    $variables['description_display'] = 'invisible';
    $variables['description_toggle'] = TRUE;
  }
}

/**
 * Implements template_preprocess_inline_entity_form_entity_table() for forms.
 */
function gin_preprocess_inline_entity_form_entity_table(array &$variables) {
  $variables['table']['#attached']['library'][] = 'gin/inline_entity_form';
}