Implement caching

src/Plugin/Block/ArchiveTreeBlock.php

@@ -96,6 +96,11 @@ class ArchiveTreeBlock extends BlockBase {
           'archive_tree/archive_tree_styles',
         ],
       ],
+      '#cache' => [
+        'contexts' => ['user', 'languages'],
+        'tags' => ['node_list'],
+        'max-age' => -1,
+      ],
     ];
   }
 }