Issue #3343978: Implement hook_help()

hierarchy_manager.module

@@ -5,6 +5,22 @@
  * General functions and hook implementations for Hierarchy Manager module.
  */
 
+use Drupal\Core\Routing\RouteMatchInterface;
+
+/**
+ * Implements hook_help().
+ */
+function hierarchy_manager_help($route_name, RouteMatchInterface $route_match) {
+  switch ($route_name) {
+    // Main module help for the hierarchy_manager module.
+    case 'help.page.hierarchy_manager':
+      $output = '<h3>' . t('About') . '</h3>';
+      $output .= '<p>' . t('Hierarchy Manager module provides a flexible solution for managing hierarchies of menu links and taxonomy terms. Unlike the default Drupal draggable table, this module supports massive hierarchies and offers a plugin architecture for customization.') . '</p>';
+      $output .= '<p>' . t('Out of the box, the module comes with two plugins: a taxonomy hierarchy management plugin and a menu hierarchy plugin. The front-end JavaScript libraries are also pluginable, with an out-of-the-box display plugin using jsTree to render the hierarchy tree with a filter. The hierarchy tree is draggable, allowing you to easily update the hierarchy by dragging a node in the tree.') . '</p>';
+    return $output;
+  }
+}
+
 /**
  * Implements hook_library_info_alter().
  */