How to include book traversal links on a custom twig template page

Alas, there is no block for this; the book navigation links are hacked on to the node view in core.

From core/modules/book/book.module:

/** * Implements hook_ENTITY_TYPE_view() for node entities. */ function book_node_view(array &$build, EntityInterface $node, EntityViewDisplayInterface $display, $view_mode) { if ($view_mode == 'full') { if (!empty($node->book['bid']) && empty($node->in_preview)) { $book_node = Node::load($node->book['bid']); if (!$book_node->access()) { return; } $build['book_navigation'] = [ '#theme' => 'book_navigation', '#book_link' => $node->book, '#weight' => 100, // The book navigation is a listing of Node entities, so associate its // list cache tag for correct invalidation. '#cache' => [ 'tags' => $node->getEntityType()->getListCacheTags(), ], ]; } } } 

The good news is that this should work with custom templates as long as you are using the full view mode.

I have a custom node template and I still get the navigation links on my books at the bottom of the content. (Unfortunately, whether I want them there or not-- as per the above code, they are forcibly added and there is no UI to control them.)

You can code the book navigation into your own block.

In this case, you will need to override book_node_view() so that the nav links are not displayed twice.

This may give you an idea (not complete code, cannot be used by itself; inspired by this post):

class BookNavigationBlock extends BlockBase { /** * {@inheritdoc} */ public function build() { $build = []; $node = \Drupal::routeMatch()->getParameter('node'); if (isset($node)) { if ($node->bundle() == 'book') { $build['book_navigation'] = [ '#theme' => 'book_navigation', '#book_link' => $node->book, '#weight' => 100, // The book navigation is a listing of Node entities, so associate its // list cache tag for correct invalidation. '#cache' => [ 'tags' => $node->getEntityType()->getListCacheTags(), ], ]; } } return $build; }