class MessageCommand in Drupal 10

AJAX command for a JavaScript Drupal.message() call.

Developers should be extra careful if this command and \Drupal\Core\Ajax\AnnounceCommand are included in the same response. Unless the `announce` option is set to an empty string (''), this command will result in the message being announced to screen readers. When combined with AnnounceCommand, this may result in unexpected behavior. Manual testing with a screen reader is strongly recommended.

Here are examples of how to suppress announcements:

$command = new MessageCommand("I won't be announced", NULL, [
  'announce' => '',
]);

Hierarchy

• class \Drupal\Core\Ajax\MessageCommand implements \Drupal\Core\Ajax\CommandInterface, \Drupal\Core\Ajax\CommandWithAttachedAssetsInterface

See also

\Drupal\Core\Ajax\AnnounceCommand

Related topics

Ajax API

Overview for Drupal's Ajax API.

2 files declare their use of MessageCommand

AjaxTestMessageCommandForm.php in core/modules/system/tests/modules/ajax_test/src/Form/AjaxTestMessageCommandForm.php

ckeditor5.module in core/modules/ckeditor5/ckeditor5.module

File

core/lib/Drupal/Core/Ajax/MessageCommand.php, line 28

Namespace

Drupal\Core\Ajax

class MessageCommand implements CommandInterface, CommandWithAttachedAssetsInterface {

  /**
   * The message text.
   *
   * @var string
   */
  protected $message;

  /**
   * Whether to clear previous messages.
   *
   * @var bool
   */
  protected $clearPrevious;

  /**
   * The query selector for the element the message will appear in.
   *
   * @var string
   */
  protected $wrapperQuerySelector;

  /**
   * The options passed to Drupal.message().add().
   *
   * @var array
   */
  protected $options;

  /**
   * Constructs a MessageCommand object.
   *
   * @param string $message
   *   The text of the message.
   * @param string|null $wrapper_query_selector
   *   The query selector of the element to display messages in when they
   *   should be displayed somewhere other than the default.
   *   @see Drupal.Message.defaultWrapper()
   * @param array $options
   *   The options passed to Drupal.message().add().
   * @param bool $clear_previous
   *   If TRUE, previous messages will be cleared first.
   */
  public function __construct($message, $wrapper_query_selector = NULL, array $options = [], $clear_previous = TRUE) {
    $this->message = $message;
    $this->wrapperQuerySelector = $wrapper_query_selector;
    $this->options = $options;
    $this->clearPrevious = $clear_previous;
  }

  /**
   * {@inheritdoc}
   */
  public function render() {
    return [
      'command' => 'message',
      'message' => $this->message,
      'messageWrapperQuerySelector' => $this->wrapperQuerySelector,
      'messageOptions' => $this->options,
      'clearPrevious' => $this->clearPrevious,
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function getAttachedAssets() {
    $assets = new AttachedAssets();
    $assets
      ->setLibraries([
      'core/drupal.message',
    ]);
    return $assets;
  }

}