Fix normalization output Data Transformer for Json format

Author: birkof

src/Serializer/ItemNormalizer.php

@@ -21,6 +21,7 @@
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
 use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
+use ApiPlatform\Core\Util\ClassInfoTrait;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
@@ -36,6 +37,8 @@
  */
 class ItemNormalizer extends AbstractItemNormalizer
 {
+    use ClassInfoTrait;
+
     private $logger;
 
     public function __construct(PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, IriConverterInterface $iriConverter, ResourceClassResolverInterface $resourceClassResolver, PropertyAccessorInterface $propertyAccessor = null, NameConverterInterface $nameConverter = null, ClassMetadataFactoryInterface $classMetadataFactory = null, ItemDataProviderInterface $itemDataProvider = null, bool $allowPlainIdentifiers = false, LoggerInterface $logger = null, DataTransformerInterface $dataTransformer = null, ResourceMetadataFactoryInterface $resourceMetadataFactory = null, $allowUnmappedClass = false)
@@ -45,6 +48,19 @@ public function __construct(PropertyNameCollectionFactoryInterface $propertyName
         $this->logger = $logger ?: new NullLogger();
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function normalize($object, $format = null, array $context = [])
+    {
+        $outputClass = $this->getOutputClass($this->getObjectClass($object), $context);
+        if (null !== $outputClass && null !== $this->dataTransformer && $this->dataTransformer->supportsTransformation($object, $outputClass, $context)) {
+            $object = $this->dataTransformer->transform($object, $outputClass, $context);
+        }
+
+        return parent::normalize($object, $format, $context);
+    }
+
     /**
      * {@inheritdoc}
      *