function comment_preview

Generates a comment preview.

Parameters

\Drupal\comment\CommentInterface $comment: The comment entity to preview.

Drupal\Core\Form\FormStateInterface $form_state: The current state of the form.

Return value

array An array as expected by \Drupal\Core\Render\RendererInterface::render().

File

core/modules/comment/comment.module, line 505

Enables users to comment on published content.

Code

function comment_preview(CommentInterface $comment, FormStateInterface $form_state) {
  $preview_build = [];
  $entity = $comment
    ->getCommentedEntity();
  if (!$form_state
    ->getErrors()) {
    $comment->in_preview = TRUE;
    $comment_build = \Drupal::entityTypeManager()
      ->getViewBuilder('comment')
      ->view($comment);
    $comment_build['#weight'] = -100;
    $preview_build['comment_preview'] = $comment_build;
  }
  if ($comment
    ->hasParentComment()) {
    $build = [];
    $parent = $comment
      ->getParentComment();
    if ($parent && $parent
      ->isPublished()) {
      $build = \Drupal::entityTypeManager()
        ->getViewBuilder('comment')
        ->view($parent);
    }
  }
  else {

    // The comment field output includes rendering the parent entity of the
    // thread to which the comment is a reply. The rendered entity output
    // includes the comment reply form, which contains the comment preview and
    // therefore the rendered parent entity. This results in an infinite loop of
    // parent entity output rendering the comment form and the comment form
    // rendering the parent entity. To prevent this infinite loop we temporarily
    // set the value of the comment field on a clone of the entity to hidden
    // before calling the entity view builder. That way when the output of
    // the commented entity is rendered, it excludes the comment field output.
    $field_name = $comment
      ->getFieldName();
    $entity = clone $entity;
    $entity->{$field_name}->status = CommentItemInterface::HIDDEN;
    $build = \Drupal::entityTypeManager()
      ->getViewBuilder($entity
      ->getEntityTypeId())
      ->view($entity, 'full');
  }
  $preview_build['comment_output_below'] = $build;
  $preview_build['comment_output_below']['#weight'] = 200;
  return $preview_build;
}