public BookManagerInterface::addFormElements(array $form

protected BookManager::buildItems(array $tree)

The node storage. Type:

public BookAdminEditForm::validateForm(array &$form

Provides handling to render the book outline. Hierarchy class \Drupal\book\

public BookOutline::__construct(BookManagerInterface $book_manager)

The entity query for node. Type:

public static BookOutlineForm::create(ContainerInterface $

public BookOutlineStorage::loadBookChildren($pid)

The book manager. Type: