settingsForm example

  public static function defaultSettings() {
    return [
      'image_style' => '',
    ];
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $element = parent::settingsForm($form, $form_state);

    unset($element['image_link'], $element['image_loading']);

    $image_styles = image_style_options(FALSE);
    $description_link = Link::fromTextAndUrl(
      $this->t('Configure Image Styles'),
      Url::fromRoute('entity.image_style.collection')
    );
    $element['image_style'] = [
      '#title' => $this->t('Image style'),
      '#type' => 'select',
      

public static function defaultSettings() {
    $settings = parent::defaultSettings();

    $settings['file_download_path'] = FALSE;
    return $settings;
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $form = parent::settingsForm($form, $form_state);

    $form['file_download_path'] = [
      '#title' => $this->t('Display the file download URI'),
      '#type' => 'checkbox',
      '#default_value' => $this->getSetting('file_download_path'),
    ];

    return $form;
  }

  /** * {@inheritdoc} */

'unicode-yes-no' => ['✔', '✖'],
      'custom' => $this->t('Custom'),
    ];

    return $formats;
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $form = parent::settingsForm($form, $form_state);

    $formats = [];
    foreach ($this->getOutputFormats() as $format_name => $format) {
      if (is_array($format)) {
        if ($format_name == 'default') {
          $formats[$format_name] = $this->t('Field settings (@on_label / @off_label)', ['@on_label' => $format[0], '@off_label' => $format[1]]);
        }
        else {
          $formats[$format_name] = $this->t('@on_label / @off_label', ['@on_label' => $format[0], '@off_label' => $format[1]]);
        }
      }
      

'#suffix' => '</div>',
    ];

    return $form;
  }

  /** * Render API callback: builds the formatter settings elements. */
  public function formatterSettingsProcessCallback(array &$element, FormStateInterface $form_state, array &$complete_form) {
    if ($formatter = $this->getFormatter($element['#parents'], $form_state)) {
      $element['settings_wrapper']['settings'] = $formatter->settingsForm($complete_form, $form_state);
      $element['settings_wrapper']['settings']['#parents'] = array_merge($element['#parents'], ['settings']);
      $element['settings_wrapper']['third_party_settings'] = $this->thirdPartySettingsForm($formatter, $this->getFieldDefinition(), $complete_form, $form_state);
      $element['settings_wrapper']['third_party_settings']['#parents'] = array_merge($element['#parents'], ['third_party_settings']);
      FormHelper::rewriteStatesSelector($element['settings_wrapper'], "fields[$this->fieldName][settings_edit_form]", 'settings[formatter]');

      // Store the array parents for our element so that we can retrieve the       // formatter settings in our AJAX callback.       $form_state->set('field_block_array_parents', $element['#array_parents']);
    }
    return $element;
  }

  

'past_format' => '@interval ago',
        'granularity' => 2,
        'refresh' => 60,
      ],
    ] + parent::defaultSettings();
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $form = parent::settingsForm($form, $form_state);

    $date_formats = [];
    foreach ($this->dateFormatStorage->loadMultiple() as $machine_name => $value) {
      $date_formats[$machine_name] = $this->t('@name format: @date', ['@name' => $value->label(), '@date' => $this->dateFormatter->format(REQUEST_TIME, $machine_name)]);
    }
    $date_formats[static::CUSTOM_DATE_FORMAT] = $this->t('Custom');

    $time_diff = $this->getSetting('time_diff');

    $form['time_diff']['#tree'] = TRUE;
    $form['time_diff']['enabled'] = [
      

public static function defaultSettings() {
    return [
      'progress_indicator' => 'throbber',
      'preview_image_style' => 'thumbnail',
    ] + parent::defaultSettings();
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $element = parent::settingsForm($form, $form_state);

    $element['preview_image_style'] = [
      '#title' => $this->t('Preview image style'),
      '#type' => 'select',
      '#options' => image_style_options(FALSE),
      '#empty_option' => '<' . $this->t('no preview') . '>',
      '#default_value' => $this->getSetting('preview_image_style'),
      '#description' => $this->t('The preview image will be shown while editing the content.'),
      '#weight' => 15,
    ];

    

return [
      'muted' => FALSE,
      'width' => 640,
      'height' => 480,
    ] + parent::defaultSettings();
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    return parent::settingsForm($form, $form_state) + [
      'muted' => [
        '#title' => $this->t('Muted'),
        '#type' => 'checkbox',
        '#default_value' => $this->getSetting('muted'),
      ],
      'width' => [
        '#type' => 'number',
        '#title' => $this->t('Width'),
        '#default_value' => $this->getSetting('width'),
        '#size' => 5,
        '#maxlength' => 5,
        

  protected function formatDate($date) {
    $format_type = $this->getSetting('format_type');
    $timezone = $this->getSetting('timezone_override') ?: $date->getTimezone()->getName();
    return $this->dateFormatter->format($date->getTimestamp(), $format_type, '', $timezone != '' ? $timezone : NULL);
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $form = parent::settingsForm($form, $form_state);

    $time = new DrupalDateTime();
    $format_types = $this->dateFormatStorage->loadMultiple();
    $options = [];
    foreach ($format_types as $type => $type_info) {
      $format = $this->dateFormatter->format($time->getTimestamp(), $type);
      $options[$type] = $type_info->label() . ' (' . $format . ')';
    }

    $form['format_type'] = [
      '#type' => 'select',
      

  protected function supportsExternalLinks() {
    $link_type = $this->getFieldSetting('link_type');
    return (bool) ($link_type & LinkItemInterface::LINK_EXTERNAL);
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $elements = parent::settingsForm($form, $form_state);

    $elements['placeholder_url'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Placeholder for URL'),
      '#default_value' => $this->getSetting('placeholder_url'),
      '#description' => $this->t('Text that will be shown inside the field until a value is entered. This hint is usually a sample value or a brief description of the expected format.'),
    ];
    $elements['placeholder_title'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Placeholder for link text'),
      '#default_value' => $this->getSetting('placeholder_title'),
      

      }
    }

    return $elements;
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $form = parent::settingsForm($form, $form_state);

    $form['separator'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Date separator'),
      '#description' => $this->t('The string to separate the start and end dates'),
      '#default_value' => $this->getSetting('separator'),
    ];

    return $form;
  }

  

  public static function defaultSettings() {
    $settings['link_to_file'] = FALSE;

    return $settings;
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $form = parent::settingsForm($form, $form_state);

    $form['link_to_file'] = [
      '#title' => $this->t('Link this field to the file download URL'),
      '#type' => 'checkbox',
      '#default_value' => $this->getSetting('link_to_file'),
    ];

    return $form;
  }

  /** * {@inheritdoc} */

'#date_increment' => $increment,
      '#date_part_order' => $date_part_order,
    ] + $element['end_value'];

    return $element;
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $element = parent::settingsForm($form, $form_state);

    $element['date_order'] = [
      '#type' => 'select',
      '#title' => $this->t('Date part order'),
      '#default_value' => $this->getSetting('date_order'),
      '#options' => ['MDY' => $this->t('Month/Day/Year'), 'DMY' => $this->t('Day/Month/Year'), 'YMD' => $this->t('Year/Month/Day')],
    ];

    if ($this->getFieldSetting('datetime_type') == DateRangeItem::DATETIME_TYPE_DATETIME) {
      $element['time_type'] = [
        '#type' => 'select',
        

'#date_increment' => $increment,
      '#date_part_order' => $date_part_order,
    ] + $element['value'];

    return $element;
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $element = parent::settingsForm($form, $form_state);

    $element['date_order'] = [
      '#type' => 'select',
      '#title' => $this->t('Date part order'),
      '#default_value' => $this->getSetting('date_order'),
      '#options' => [
        'MDY' => $this->t('Month/Day/Year'),
        'DMY' => $this->t('Day/Month/Year'),
        'YMD' => $this->t('Year/Month/Day'),
      ],
    ];

    

  public static function defaultSettings() {
    return [
      'separator' => '-',
    ] + parent::defaultSettings();
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $form = parent::settingsForm($form, $form_state);

    $form['separator'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Date separator'),
      '#description' => $this->t('The string to separate the start and end dates'),
      '#default_value' => $this->getSetting('separator'),
    ];

    return $form;
  }

  

  protected function formatDate($date) {
    $format = $this->getSetting('date_format');
    $timezone = $this->getSetting('timezone_override') ?: $date->getTimezone()->getName();
    return $this->dateFormatter->format($date->getTimestamp(), 'custom', $format, $timezone != '' ? $timezone : NULL);
  }

  /** * {@inheritdoc} */
  public function settingsForm(array $form, FormStateInterface $form_state) {
    $form = parent::settingsForm($form, $form_state);

    $form['date_format'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Date/time format'),
      '#description' => $this->t('See <a href="https://www.php.net/manual/datetime.format.php#refsect1-datetime.format-parameters" target="_blank">the documentation for PHP date formats</a>.'),
      '#default_value' => $this->getSetting('date_format'),
    ];

    return $form;
  }