Sort 'Works Cited' list by author, title.

bibcite_footnotes.module

@@ -314,3 +314,52 @@ function bibcite_footnotes_get_ckeditor_select_item($entity): array {
   $citation_key = $entity->id->first()->getValue()['value'];
   return [$citation_text, $citation_key];
 }
+
+/**
+ * Implementation of hook_preprocess_field().
+ * Sor the works cited list by rendered text, which results in author(s) then title.
+ *
+ * @param $variables
+ * @param $hook
+ */
+function bibcite_footnotes_preprocess_field(&$variables, $hook) {
+  $citation_tools = new CitationTools();
+  if ($variables['field_name'] == 'field_bibcite_fn_works_cited') {
+
+    foreach($variables['element'] as $index => $element) {
+      if (is_numeric($index)) {
+        $renderable = $citation_tools->getRenderableReference($element['#bibcite_reference']);
+        $items[] = [
+          'orig_index' => $index,
+          'orig_element' => $element,
+          'rendered' => trim(strip_tags(render($renderable))),
+        ];
+      }
+    }
+    uasort($items, '_bibcite_footnotes_sort_rendered_references');
+    $i = 0;
+    foreach ($items as $item) {
+      $variables['element'][$i] = $item['orig_element'];
+      $variables['element']['#items'][$i] = $item['orig_element'];
+      $variables['items'][$i]['content'] = $item['orig_element'];
+      $i += 1;
+    }
+  }
+}
+
+/**
+ * Comparator function for theme field preprocess.
+ *
+ * @param $a
+ *   The first renderable element.
+ * @param $b
+ *   The second renderable element.
+ *
+ * @return int
+ */
+function _bibcite_footnotes_sort_rendered_references($a, $b) {
+  if ($a['rendered'] == $b['rendered']) {
+    return 0;
+  }
+  return strtolower($a['rendered']) < strtolower($b['rendered']) ? -1 : 1;
+}

src/CitationTools.php

@@ -11,12 +11,14 @@ namespace Drupal\bibcite_footnotes;
 
 class CitationTools {
 
-  public function getRenderableReference($reference_entity_id) {
+  public function getRenderableReference($reference_entity) {
-    $reference_storage = \Drupal::entityTypeManager()
+    if (is_numeric($reference_entity)) {
+      $reference_entity = \Drupal::entityTypeManager()
         ->getStorage('bibcite_reference')
-      ->load($reference_entity_id);
+        ->load($reference_entity);
+    }
     $serializer = \Drupal::service('serializer');
-    $data = $serializer->normalize($reference_storage, 'csl');
+    $data = $serializer->normalize($reference_entity, 'csl');
     return ['#theme' => 'bibcite_citation', '#data' => $data];
   }
 }