config/constants.ts

@@ -1,4 +1,5 @@
 import { Environment } from "@paypal/paypal-server-sdk";
+import { vatDecimal } from "../src/checkout/vat";
 
 export const pdfApiUrl = process.env.PDF_API_ADDRESS!;
 export const mailApiUrl = process.env.MAIL_API_ADDRESS!;
@@ -18,10 +19,7 @@ export const shopEmail = process.env.SHOP_EMAIL ?? process.env.ADMIN_EMAIL_ADDRE
 export const shopLogoUrl = process.env.SHOP_LOGO_URL ?? "";
 export const shopSecondaryLogoUrl = process.env.SHOP_SECONDARY_LOGO_URL ?? "";
 
-// TODO: Should be retrieved from DepotApi
-export const vatIncludedDecimal = 1.19;
-// TODO: Should be retrieved from DepotApi
-export const vatDecimal = 0.19;
+export { vatIncludedDecimal, vatDecimal } from "../src/checkout/vat";
 export const vatDecimalExcluded = 1 - vatDecimal;
 
 export const maxProductsSitemap = 500;

src/api/product/services/product.ts

@@ -3,7 +3,7 @@
  */
 
 import { factories } from "@strapi/strapi";
-import { Product } from "../../../../types";
+import { calculateTotalProductPrice } from "../../../checkout/pricing";
 
 export default factories.createCoreService("api::product.product", ({ strapi }) => ({
 	find: async (params: Record<string, any>) => {
@@ -110,9 +110,8 @@ export default factories.createCoreService("api::product.product", ({ strapi })
 	}
 }));
 
-export const calculateTotalProductPrice = (product: Partial<Product>): number => {
-	return (product?.cover?.price ?? 0) + (product?.pages?.price ?? 0) + (product?.ruling?.price ?? 0);
-};
+// Implemented in src/checkout/pricing.ts; re-exported so existing importers keep working.
+export { calculateTotalProductPrice };
 
 export interface ProductParams {
 	populate?: {

src/checkout/paypal-order.ts

@@ -0,0 +1,124 @@
+import type { Order } from "../../types";
+import { calculateTotalProductPrice } from "./pricing";
+import { vatIncludedDecimal } from "./vat";
+
+// The PayPal order that PayPalApi.createSessionOrThrow creates, built without the PayPal SDK so it can be unit tested.
+// String literals stand in for the SDK enums, with the values of @paypal/paypal-server-sdk 0.6.1.
+
+export type PayPalMoney = {
+	currencyCode: string;
+	value: string;
+};
+
+export type PayPalOrderItem = {
+	name: string;
+	unitAmount: PayPalMoney;
+	tax: PayPalMoney;
+	quantity: string;
+};
+
+export type PayPalOrderRequest = {
+	/** CheckoutPaymentIntent.Capture */
+	intent: "CAPTURE";
+	purchaseUnits: {
+		referenceId: string;
+		amount: PayPalMoney & {
+			breakdown: {
+				itemTotal: PayPalMoney;
+				taxTotal: PayPalMoney;
+				shipping: PayPalMoney | undefined;
+			};
+		};
+		shipping: {
+			name: { fullName: string };
+			address: { addressLine1: string; postalCode: string; adminArea2: string; countryCode: string };
+		};
+		customId: string;
+		invoiceId: string;
+	}[];
+	applicationContext: {
+		returnUrl: string;
+		cancelUrl: string;
+		/** OrderApplicationContextShippingPreference.SetProvidedAddress */
+		shippingPreference: "SET_PROVIDED_ADDRESS";
+	};
+};
+
+/**
+ * The part of PayPalApi.createSessionOrThrow that runs before its try block, so nothing thrown here is logged there.
+ * Rejects an order without a total, then computes one item per cart line. The items are not sent to PayPal, but computing
+ * them throws a TypeError for a cart line without a product.
+ */
+export const buildPayPalOrderItems = (order: Order): PayPalOrderItem[] => {
+	if (!order.total) throw new Error("Cart is empty or has no total");
+
+	return order.cart.map((item) => {
+		const totalProductPrice = calculateTotalProductPrice(item.product);
+		const amount = totalProductPrice / vatIncludedDecimal;
+		const tax = totalProductPrice - amount;
+
+		return {
+			name: item.product.name,
+			unitAmount: {
+				currencyCode: "EUR",
+				value: amount.toFixed(2)
+			},
+			tax: {
+				currencyCode: "EUR",
+				value: tax.toFixed(2)
+			},
+			quantity: item.count.toString()
+		};
+	});
+};
+
+/**
+ * The order request body PayPalApi.createSessionOrThrow sends. It is built inside that try block, so whatever throws here is logged there.
+ */
+export const buildPayPalOrderRequest = (returnUrl: string, order: Order): PayPalOrderRequest => ({
+	intent: "CAPTURE",
+	purchaseUnits: [
+		{
+			// items: computed by buildPayPalOrderItems, but not sent
+			referenceId: order.uuid,
+			amount: {
+				currencyCode: "EUR",
+				value: order.total.toFixed(2),
+				breakdown: {
+					itemTotal: {
+						currencyCode: "EUR",
+						value: (Math.round((order.subtotal / vatIncludedDecimal) * 100) / 100).toFixed(2)
+					},
+					taxTotal: {
+						currencyCode: "EUR",
+						value: order.VAT.toFixed(2)
+					},
+					shipping: order.delivery
+						? {
+								currencyCode: "EUR",
+								value: order.delivery.price.toFixed(2)
+							}
+						: undefined
+				}
+			},
+			shipping: {
+				name: {
+					fullName: order.deliveryAddress.split("\n")[0]
+				},
+				address: {
+					addressLine1: order.deliveryAddress.split("\n")[1],
+					postalCode: order.deliveryAddress.split("\n")[2].slice(0, 5),
+					adminArea2: order.deliveryAddress.split("\n")[2].slice(6),
+					countryCode: "DE"
+				}
+			},
+			customId: order.uuid,
+			invoiceId: order.invoiceNumber
+		}
+	],
+	applicationContext: {
+		returnUrl: returnUrl,
+		cancelUrl: returnUrl,
+		shippingPreference: "SET_PROVIDED_ADDRESS"
+	}
+});

src/checkout/pricing.ts

@@ -0,0 +1,5 @@
+import type { Product } from "../../types";
+
+export const calculateTotalProductPrice = (product: Partial<Product>): number => {
+	return (product?.cover?.price ?? 0) + (product?.pages?.price ?? 0) + (product?.ruling?.price ?? 0);
+};

src/checkout/vat.ts

@@ -0,0 +1,4 @@
+// TODO: Should be retrieved from DepotApi
+export const vatIncludedDecimal = 1.19;
+// TODO: Should be retrieved from DepotApi
+export const vatDecimal = 0.19;

src/services/PayPalApi.ts

@@ -1,16 +1,7 @@
-import {
-	Client,
-	Environment,
-	LogLevel,
-	OrdersController,
-	CheckoutPaymentIntent,
-	OrderRequest,
-	OrderApplicationContextShippingPreference,
-	Item
-} from "@paypal/paypal-server-sdk";
-import { paypalClientId, paypalClientSecret, paypalEnvironment, vatIncludedDecimal, vatDecimalExcluded } from "../../config/constants";
+import { Client, Environment, LogLevel, OrdersController, OrderRequest } from "@paypal/paypal-server-sdk";
+import { paypalClientId, paypalClientSecret, paypalEnvironment } from "../../config/constants";
 import { Order } from "../../types";
-import { calculateTotalProductPrice } from "../api/product/services/product";
+import { buildPayPalOrderItems, buildPayPalOrderRequest } from "../checkout/paypal-order";
 
 class PayPalApi {
 	private readonly client: Client;
@@ -34,76 +25,12 @@ class PayPalApi {
 	}
 
 	async createSessionOrThrow(returnUrl: string, order: Order) {
-		if (!order.total) throw new Error("Cart is empty or has no total");
-
-		const items = order.cart.map((item) => {
-			const totalProductPrice = calculateTotalProductPrice(item.product);
-			const amount = totalProductPrice / vatIncludedDecimal;
-			const tax = totalProductPrice - amount;
-
-			return {
-				name: item.product.name,
-				unitAmount: {
-					currencyCode: "EUR",
-					value: amount.toFixed(2)
-				},
-				tax: {
-					currencyCode: "EUR",
-					value: tax.toFixed(2)
-				},
-				quantity: item.count.toString()
-			} as Item;
-		});
+		// Outside the try block, so these throws are not logged here. The items are computed but not sent.
+		buildPayPalOrderItems(order);
 
 		try {
 			const collect = {
-				body: {
-					intent: CheckoutPaymentIntent.Capture,
-					purchaseUnits: [
-						{
-							// items,
-							referenceId: order.uuid,
-							amount: {
-								currencyCode: "EUR",
-								value: order.total.toFixed(2),
-								breakdown: {
-									itemTotal: {
-										currencyCode: "EUR",
-										value: (Math.round((order.subtotal / vatIncludedDecimal) * 100) / 100).toFixed(2)
-									},
-									taxTotal: {
-										currencyCode: "EUR",
-										value: order.VAT.toFixed(2)
-									},
-									shipping: order.delivery
-										? {
-												currencyCode: "EUR",
-												value: order.delivery.price.toFixed(2)
-											}
-										: undefined
-								}
-							},
-							shipping: {
-								name: {
-									fullName: order.deliveryAddress.split("\n")[0]
-								},
-								address: {
-									addressLine1: order.deliveryAddress.split("\n")[1],
-									postalCode: order.deliveryAddress.split("\n")[2].slice(0, 5),
-									adminArea2: order.deliveryAddress.split("\n")[2].slice(6),
-									countryCode: "DE"
-								}
-							},
-							customId: order.uuid,
-							invoiceId: order.invoiceNumber
-						}
-					],
-					applicationContext: {
-						returnUrl: returnUrl,
-						cancelUrl: returnUrl,
-						shippingPreference: OrderApplicationContextShippingPreference.SetProvidedAddress
-					}
-				} as OrderRequest,
+				body: buildPayPalOrderRequest(returnUrl, order) as OrderRequest,
 				prefer: "return=minimal"
 			};