From f78d5fcc5df199611b980cfb591a36efa5efa215 Mon Sep 17 00:00:00 2001
From: Jakub Majorek <majorek.jakub@gmail.com>
Date: Tue, 7 Dec 2021 10:44:49 +0100
Subject: [PATCH] Fix initial discount calculation on draft order line (#1651)

---
 src/hooks/useUpdateEffect.ts                       | 14 ++++++++++++++
 .../OrderDiscountCommonModal.tsx                   |  3 ++-
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 src/hooks/useUpdateEffect.ts

diff --git a/src/hooks/useUpdateEffect.ts b/src/hooks/useUpdateEffect.ts
new file mode 100644
index 000000000..de194a632
--- /dev/null
+++ b/src/hooks/useUpdateEffect.ts
@@ -0,0 +1,14 @@
+import { useEffect, useRef } from "react";
+
+export function useUpdateEffect(fn: () => void, depArr: any[]) {
+  const mounted = useRef(false);
+
+  useEffect(() => {
+    if (mounted.current) {
+      return fn();
+    }
+    mounted.current = true;
+  }, depArr);
+}
+
+export default useUpdateEffect;
diff --git a/src/orders/components/OrderDiscountCommonModal/OrderDiscountCommonModal.tsx b/src/orders/components/OrderDiscountCommonModal/OrderDiscountCommonModal.tsx
index c74a63adf..0c661504f 100644
--- a/src/orders/components/OrderDiscountCommonModal/OrderDiscountCommonModal.tsx
+++ b/src/orders/components/OrderDiscountCommonModal/OrderDiscountCommonModal.tsx
@@ -14,6 +14,7 @@ import ConfirmButton, {
 import PriceField from "@saleor/components/PriceField";
 import RadioGroupField from "@saleor/components/RadioGroupField";
 import { Money } from "@saleor/fragments/types/Money";
+import { useUpdateEffect } from "@saleor/hooks/useUpdateEffect";
 import { buttonMessages } from "@saleor/intl";
 import { makeStyles } from "@saleor/macaw-ui";
 import { DiscountValueTypeEnum } from "@saleor/types/globalTypes";
@@ -258,7 +259,7 @@ const OrderDiscountCommonModal: React.FC<OrderDiscountCommonModalProps> = ({
     setValue(recalculatedValue);
   };
 
-  useEffect(handleValueConversion, [calculationMode]);
+  useUpdateEffect(handleValueConversion, [calculationMode]);
 
   const dialogTitle =
     modalType === ORDER_LINE_DISCOUNT