Support nullable return (#60)

Author: Casperhr

src/Fractal.php

@@ -362,7 +362,7 @@ public function toJson($options = 0)
     /**
      * Perform the transformation to array.
      *
-     * @return array
+     * @return array|null
      */
     public function toArray()
     {
@@ -455,10 +455,10 @@ public function getResourceName()
     /**
      * Convert the object into something JSON serializable.
      *
-     * @return array
+     * @return array|null
      */
     #[\ReturnTypeWillChange]
-    public function jsonSerialize(): array
+    public function jsonSerialize(): ?array
     {
         return $this->toArray();
     }