fix(core): TRAC-294 show manual checkout discounts in cart summary (#3002)

Author: bc-alexsaiannyi

.changeset/cold-foxes-lie.md

@@ -0,0 +1,5 @@
+---
+"@bigcommerce/catalyst-core": patch
+---
+
+Fix cart summary Discounts row not showing manual discounts applied via the Management Checkout API

core/app/[locale]/(default)/cart/page-data.ts

@@ -28,6 +28,10 @@ export const PhysicalItemFragment = graphql(`
       currencyCode
       value
     }
+    discountedAmount {
+      currencyCode
+      value
+    }
     selectedOptions {
       __typename
       entityId
@@ -87,6 +91,10 @@ export const DigitalItemFragment = graphql(`
       currencyCode
       value
     }
+    discountedAmount {
+      currencyCode
+      value
+    }
     selectedOptions {
       __typename
       entityId

core/app/[locale]/(default)/cart/page.tsx

@@ -213,6 +213,13 @@ export default async function Cart({ params }: Props) {
   const totalCouponDiscount =
     checkout?.coupons.reduce((sum, coupon) => sum + coupon.discountedAmount.value, 0) ?? 0;
 
+  const totalLineItemDiscount = [
+    ...cart.lineItems.physicalItems,
+    ...cart.lineItems.digitalItems,
+  ].reduce((sum, item) => sum + item.discountedAmount.value, 0);
+
+  const totalDiscount = cart.discountedAmount.value + totalLineItemDiscount;
+
   const giftCertificatesSummary =
     checkout?.giftCertificates.reduce<Array<{ code: string; used: number }>>((acc, c) => {
       acc.push({
@@ -278,10 +285,10 @@ export default async function Cart({ params }: Props) {
                   currency: cart.currencyCode,
                 }),
               },
-              cart.discountedAmount.value > 0
+              totalDiscount > 0
                 ? {
                     label: t('CheckoutSummary.discounts'),
-                    value: `-${format.number(cart.discountedAmount.value, {
+                    value: `-${format.number(totalDiscount, {
                       style: 'currency',
                       currency: cart.currencyCode,
                     })}`,