Use native json_encode to convert treeView objects to JSON.

This should improve the performance.

src/Controller/TreeController.php

@@ -33,6 +33,7 @@ use App\Services\Trees\ToolsTreeBuilder;
 use App\Services\Trees\NodesListBuilder;
 use App\Services\Trees\TreeViewGenerator;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\JsonResponse;
 use Symfony\Component\Routing\Annotation\Route;
 
 /**
@@ -54,8 +55,7 @@ class TreeController extends AbstractController
     public function tools(ToolsTreeBuilder $builder)
     {
         $tree = $builder->getTree();
-        //Ignore null values, to save data
-        return $this->json($tree, 200, [], ['skip_null_values' => true]);
+        return new JsonResponse($tree);
     }
 
     /**
@@ -65,7 +65,7 @@ class TreeController extends AbstractController
     public function categoryTree(Category $category = null)
     {
         $tree = $this->treeGenerator->getTreeView(Category::class, $category);
-        return $this->json($tree, 200, [], ['skip_null_values' => true]);
+        return new JsonResponse($tree);
     }
 
     /**
@@ -75,7 +75,7 @@ class TreeController extends AbstractController
     public function footprintTree(Footprint $footprint = null)
     {
         $tree = $this->treeGenerator->getTreeView(Footprint::class, $footprint);
-        return $this->json($tree, 200, [], ['skip_null_values' => true]);
+        return new JsonResponse($tree);
     }
 
     /**
@@ -85,7 +85,7 @@ class TreeController extends AbstractController
     public function locationTree(Storelocation $location = null)
     {
         $tree = $this->treeGenerator->getTreeView(Storelocation::class, $location);
-        return $this->json($tree, 200, [], ['skip_null_values' => true]);
+        return new JsonResponse($tree);
     }
 
     /**
@@ -95,7 +95,7 @@ class TreeController extends AbstractController
     public function manufacturerTree(Manufacturer $manufacturer = null)
     {
         $tree = $this->treeGenerator->getTreeView(Manufacturer::class, $manufacturer);
-        return $this->json($tree, 200, [], ['skip_null_values' => true]);
+        return new JsonResponse($tree);
     }
 
     /**
@@ -105,7 +105,7 @@ class TreeController extends AbstractController
     public function supplierTree(Supplier $supplier = null)
     {
         $tree = $this->treeGenerator->getTreeView(Supplier::class, $supplier);
-        return $this->json($tree, 200, [], ['skip_null_values' => true]);
+        return new JsonResponse($tree);
     }
 
     /**
@@ -115,6 +115,6 @@ class TreeController extends AbstractController
     public function deviceTree(Device $device = null)
     {
         $tree = $this->treeGenerator->getTreeView(Device::class, $device, '');
-        return $this->json($tree, 200, [], ['skip_null_values' => true]);
+        return new JsonResponse($tree);
     }
 }

src/Helpers/Trees/TreeViewNode.php

@@ -30,7 +30,7 @@ use App\Helpers\Trees\TreeViewNodeState;
  * This class represents a node for the bootstrap treeview node.
  * When you serialize an array of these objects to JSON, you can use the serialized data in data for the treeview.
  */
-class TreeViewNode
+class TreeViewNode implements \JsonSerializable
 {
     protected $text;
     protected $href;
@@ -206,4 +206,32 @@ class TreeViewNode
 
         return $this;
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function jsonSerialize()
+    {
+        $ret = [
+            'text' => $this->text
+        ];
+
+        if($this->href !== null) {
+            $ret['href'] = $this->href;
+        }
+
+        if($this->tags !== null) {
+            $ret['tags'] = $this->tags;
+        }
+
+        if($this->nodes !== null) {
+            $ret['nodes'] = $this->nodes;
+        }
+
+        if($this->state !== null) {
+            $ret['state'] = $this->state;
+        }
+
+        return $ret;
+    }
 }

src/Helpers/Trees/TreeViewNodeState.php

@@ -21,7 +21,7 @@
 
 namespace App\Helpers\Trees;
 
-class TreeViewNodeState
+class TreeViewNodeState implements \JsonSerializable
 {
     /** @var bool|null */
     protected $checked = null;
@@ -73,4 +73,25 @@ class TreeViewNodeState
     {
         $this->selected = $selected;
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function jsonSerialize()
+    {
+        $ret = [];
+        if ($this->selected !== null) {
+            $ret['selected'] = $this->selected;
+        }
+
+        if($this->disabled !== null) {
+            $ret['disabled'] = $this->disabled;
+        }
+
+        if($this->expanded !== null) {
+            $ret['expanded'] = $this->expanded;
+        }
+
+        return $ret;
+    }
 }

src/Twig/AppExtension.php

@@ -106,7 +106,7 @@ class AppExtension extends AbstractExtension
     {
         $tree = $this->treeBuilder->getTreeView(\get_class($element), null, $type, $element);
 
-        return $this->serializer->serialize($tree, 'json', ['skip_null_values' => true]);
+        return json_encode($tree);
     }
 
     /**