B2B-2469: Improve category children loading

- CR fixes

Author: rganin

app/code/Magento/CatalogGraphQl/Model/Resolver/CategoryList.php

@@ -103,7 +103,7 @@ public function resolve(Field $field, $context, ResolveInfo $info, array $value
      *
      * @param array $topLevelCategoryIds
      * @param ResolveInfo $info
-     * @param array $criteria
+     * @param array $processedArgs
      * @param array $attributeNames
      * @param ContextInterface $context
      * @return array
@@ -112,13 +112,14 @@ public function resolve(Field $field, $context, ResolveInfo $info, array $value
     private function fetchCategoriesByTopLevelIds(
         array $topLevelCategoryIds,
         ResolveInfo $info,
-        array $criteria,
+        array $processedArgs,
         array $attributeNames,
         ContextInterface $context
     ) : array {
-        $criteria['pageSize'] = 0;
+        // pagination must be applied to top level category results, children categories are not paginated
+        $processedArgs['pageSize'] = 0;
         $searchCriteria = $this->searchCriteria->buildCriteria(
-            $criteria,
+            $processedArgs,
             $context->getExtensionAttributes()->getStore()
         );
         $categoryCollection = $this->categoryTree->getFlatCategoriesByRootIds(

app/code/Magento/CatalogGraphQl/Model/Resolver/Products/DataProvider/CategoryTree/Wrapper/Node.php

@@ -81,7 +81,7 @@ public function getId(): int
     }
 
     /**
-     * Render node and its children as an array recursively, returns null is node model is not set.
+     * Render node and its children as an array recursively, returns null if node data is not set.
      *
      * @return array|null
      */

app/code/Magento/CatalogGraphQl/Model/Resolver/Products/DataProvider/CategoryTree/Wrapper/NodeWrapper.php

@@ -22,11 +22,11 @@ class NodeWrapper
     private const TOP_NODE_ID = 0;
 
     /**
-     * Flat index of the tree.
+     * Flat index of the tree that stores nodes by entity identifier.
      *
      * @var array
      */
-    private array $index = [];
+    private array $nodesById = [];
 
     /**
      * @var Hydrator
@@ -49,21 +49,21 @@ public function __construct(Hydrator $hydrator)
      */
     public function wrap(Category $category): void
     {
-        if (!isset($this->index[self::TOP_NODE_ID])) {
-            $this->index[self::TOP_NODE_ID] = new Node(self::TOP_NODE_ID);
+        if (!isset($this->nodesById[self::TOP_NODE_ID])) {
+            $this->nodesById[self::TOP_NODE_ID] = new Node(self::TOP_NODE_ID);
         }
         $parentId = self::TOP_NODE_ID;
         array_map(
             function ($id) use (&$parentId, $category) {
                 $id = (int)$id;
-                if (!isset($this->index[$id])) {
-                    $this->index[$id] = new Node($id);
+                if (!isset($this->nodesById[$id])) {
+                    $this->nodesById[$id] = new Node($id);
                     if ($category->getId() == $id) {
-                        $this->index[$id]->setModelData(
+                        $this->nodesById[$id]->setModelData(
                             $this->hydrator->hydrateCategory($category)
                         );
                     }
-                    $this->index[$parentId]->addChild($this->index[$id]);
+                    $this->nodesById[$parentId]->addChild($this->nodesById[$id]);
                 }
                 $parentId = $id;
             },
@@ -77,8 +77,8 @@ function ($id) use (&$parentId, $category) {
      * @param int $id
      * @return Node|null
      */
-    public function getNode(int $id) : ?Node
+    public function getNodeById(int $id) : ?Node
     {
-        return $this->index[$id] ?? null;
+        return $this->nodesById[$id] ?? null;
     }
 }

app/code/Magento/CatalogGraphQl/Model/Resolver/Products/DataProvider/ExtractDataFromCategoryTree.php

@@ -45,7 +45,7 @@ public function buildTree(Collection $collection, array $topLevelCategories) : a
         }
         $tree = [];
         foreach ($topLevelCategories as $topLevelCategory) {
-            $tree[] = $wrapper->getNode($topLevelCategory)->renderArray();
+            $tree[] = $wrapper->getNodeById($topLevelCategory)->renderArray();
         }
         return $this->sortTree($tree);
     }