From a813e1677a3d34627bd396af295ab1f025d464d3 Mon Sep 17 00:00:00 2001
From: Dennis Eichhorn <spl1nes.com@googlemail.com>
Date: Wed, 9 Nov 2022 23:02:52 +0100
Subject: [PATCH] reduce serialization of null models

---
 Models/NullBill.php        | 8 ++++++++
 Models/NullBillElement.php | 8 ++++++++
 Models/NullBillType.php    | 8 ++++++++
 3 files changed, 24 insertions(+)

diff --git a/Models/NullBill.php b/Models/NullBill.php
index 89a5b22..0fce6ea 100755
--- a/Models/NullBill.php
+++ b/Models/NullBill.php
@@ -36,4 +36,12 @@ final class NullBill extends Bill
         $this->id = $id;
         parent::__construct();
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function jsonSerialize() : mixed
+    {
+        return ['id' => $this->id];
+    }
 }
diff --git a/Models/NullBillElement.php b/Models/NullBillElement.php
index a7ad65e..77a5719 100755
--- a/Models/NullBillElement.php
+++ b/Models/NullBillElement.php
@@ -36,4 +36,12 @@ final class NullBillElement extends BillElement
         $this->id = $id;
         parent::__construct();
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function jsonSerialize() : mixed
+    {
+        return ['id' => $this->id];
+    }
 }
diff --git a/Models/NullBillType.php b/Models/NullBillType.php
index 1cba56c..2e366b8 100755
--- a/Models/NullBillType.php
+++ b/Models/NullBillType.php
@@ -36,4 +36,12 @@ final class NullBillType extends BillType
         $this->id = $id;
         parent::__construct();
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function jsonSerialize() : mixed
+    {
+        return ['id' => $this->id];
+    }
 }