class Password

class Password extends FormElementBase {

  /**
   * {@inheritdoc}
   */
  public function getInfo() {
    $class = static::class;
    return [
      '#input' => TRUE,
      '#size' => 60,
      '#maxlength' => 128,
      '#process' => [
        [
          $class,
          'processAjaxForm',
        ],
        [
          $class,
          'processPattern',
        ],
      ],
      '#pre_render' => [
        [
          $class,
          'preRenderPassword',
        ],
      ],
      '#theme' => 'input__password',
      '#theme_wrappers' => [
        'form_element',
      ],
    ];
  }

  /**
   * Prepares a #type 'password' render element for input.html.twig.
   *
   * @param array $element
   *   An associative array containing the properties of the element.
   *   Properties used: #title, #value, #description, #size, #maxlength,
   *   #placeholder, #required, #attributes.
   *
   * @return array
   *   The $element with prepared variables ready for input.html.twig.
   */
  public static function preRenderPassword($element) {
    $element['#attributes']['type'] = 'password';
    Element::setAttributes($element, [
      'id',
      'name',
      'size',
      'maxlength',
      'placeholder',
    ]);
    static::setAttributes($element, [
      'form-text',
    ]);
    return $element;
  }

  /**
   * {@inheritdoc}
   */
  public static function valueCallback(&$element, $input, FormStateInterface $form_state) {
    if ($input !== FALSE && $input !== NULL) {

      // This should be a string, but allow other scalars since they might be
      // valid input in programmatic form submissions.
      return is_scalar($input) ? (string) $input : '';
    }
    return NULL;
  }

}