Issue #1987406 by jenlampton, Petr Illek, forbesgraham, herom, jerdavis, Jon Pugh, sanguis, idflood, ezeedub, shanethehat, joelpittet | Cottser: Node.module - Convert theme_ functions to Twig.

core/modules/node/node.module

@@ -157,10 +157,12 @@ function node_theme() {
     'node_add_list' => array(
       'variables' => array('content' => NULL),
       'file' => 'node.pages.inc',
+      'template' => 'node-add-list',
     ),
     'node_preview' => array(
       'variables' => array('node' => NULL),
       'file' => 'node.pages.inc',
+      'template' => 'node-preview',
     ),
     'node_edit_form' => array(
       'render element' => 'form',

core/modules/node/node.pages.inc

@@ -13,31 +13,27 @@ use Symfony\Component\HttpFoundation\RedirectResponse;
 use Drupal\node\NodeInterface;
 
 /**
- * Returns HTML for a list of available node types for node creation.
+ * Prepares variables for list of available node type templates.
  *
- * @param $variables
+ * Default template: node-add-list.html.twig.
+ *
+ * @param array $variables
  *   An associative array containing:
  *   - content: An array of content types.
  *
  * @see node_add_page()
- *
- * @ingroup themeable
  */
-function theme_node_add_list($variables) {
-  $content = $variables['content'];
-
-  if ($content) {
-    $output = '<dl class="node-type-list">';
-    foreach ($content as $type) {
-      $output .= '<dt>' . l($type->name, 'node/add/' . $type->type) . '</dt>';
-      $output .= '<dd>' . filter_xss_admin($type->description) . '</dd>';
+function template_preprocess_node_add_list(&$variables) {
+  $variables['types'] = array();
+  if (!empty($variables['content'])) {
+    foreach ($variables['content'] as $type) {
+      $variables['types'][$type->type] = array(
+        'type' => $type->type,
+        'add_link' => l($type->name, 'node/add/' . $type->type),
+        'description' => filter_xss_admin($type->description),
+      );
     }
-    $output .= '</dl>';
   }
-  else {
-    $output = '<p>' . t('You have not created any content types yet. Go to the <a href="@create-content">content type creation page</a> to add a new content type.', array('@create-content' => url('admin/structure/types/add'))) . '</p>';
-  }
-  return $output;
 }
 
 /**
@@ -72,41 +68,37 @@ function node_preview(NodeInterface $node, array &$form_state) {
 }
 
 /**
- * Returns HTML for a node preview for display during node creation and editing.
+ * Prepares variables for node preview templates.
  *
- * @param $variables
+ * Default template: node-preview.html.twig.
+ *
+ * @param array $variables
  *   An associative array containing:
  *   - node: The node entity which is being previewed.
  *
  * @see NodeFormController::preview()
  * @see node_preview()
- *
- * @ingroup themeable
  */
-function theme_node_preview($variables) {
+function template_preprocess_node_preview(&$variables) {
   $node = $variables['node'];
 
-  $output = '';
+  // Render trimmed teaser version of the post.
+  $node_teaser = node_view($node, 'teaser');
+  $node_teaser['#attached']['library'][] = array('node', 'drupal.node.preview');
+  $variables['teaser'] = $node_teaser;
+  // Render full version of the post.
+  $node_full = node_view($node, 'full');
+  $variables['full'] = $node_full;
 
-  $elements = node_view($node, 'teaser');
-  $elements['#attached']['library'][] = array('node', 'drupal.node.preview');
-  $trimmed = drupal_render($elements);
-  $elements = node_view($node, 'full');
-  $full = drupal_render($elements);
-
-  // Do we need to preview trimmed version of post as well as full version?
-  if ($trimmed != $full) {
+  // Display a preview of the teaser only if the content of the teaser is
+  // different to the full post.
+  if ($variables['teaser'] != $variables['full']) {
     drupal_set_message(t('The trimmed version of your post shows what your post looks like when promoted to the main page or when exported for syndication.<span class="no-js"> You can insert the delimiter "&lt;!--break--&gt;" (without the quotes) to fine-tune where your post gets split.</span>'));
-    $output .= '<h3>' . t('Preview trimmed version') . '</h3>';
-    $output .= $trimmed;
-    $output .= '<h3>' . t('Preview full version') . '</h3>';
-    $output .= $full;
+    $variables['preview_teaser'] = TRUE;
   }
   else {
-    $output .= $full;
+    $variables['preview_teaser'] = FALSE;
   }
-
-  return $output;
 }
 
 /**

core/modules/node/templates/node-add-list.html.twig

@@ -0,0 +1,32 @@
+{#
+/**
+ * @file
+ * Default theme implementation to list node types available for adding content.
+ *
+ * This list is displayed on the Add content admin page.
+ *
+ * Available variables:
+ * - types: A list of content types, each with the following properties:
+ *   - add_link: Link to create a piece of content of this type.
+ *   - description: Description of this type of content.
+ *
+ * @see template_preprocess_node_add_list()
+ *
+ * @ingroup themeable
+ */
+#}
+{% if types is not empty %}
+  <dl class="node-type-list">
+    {% for type in types %}
+      <dt>{{ type.add_link }}</dt>
+      <dd>{{ type.description }}</dd>
+    {% endfor %}
+  </dl>
+{% else %}
+  <p>
+    {% set create_content = url('admin/structure/types/add') %}
+    {% trans %}
+      You have not created any content types yet. Go to the <a href="{{ create_content }}">content type creation page</a> to add a new content type.
+    {% endtrans %}
+  </p>
+{% endif %}

core/modules/node/templates/node-preview.html.twig

@@ -0,0 +1,23 @@
+{#
+/**
+ * @file
+ * Default theme implementation for a node preview.
+ *
+ * This display may be used during node creation and editing.
+ *
+ * Available variables:
+ * - preview_teaser: Flag indicating whether to show a trimmed teaser version.
+ * - teaser: Trimmed teaser version of the node.
+ * - full: Full version of the node.
+ *
+ * @see template_preprocess_node_preview()
+ *
+ * @ingroup themeable
+ */
+#}
+{% if preview_teaser %}
+  <h3>{{ "Preview trimmed version"|t }}</h3>
+  {{ teaser }}
+  <h3>{{ "Preview full version"|t }}</h3>
+{% endif %}
+{{ full }}