feat: add cartLoader to batch User.cart resolution

packages/api/src/loaders/cartLoader.ts

@@ -0,0 +1,25 @@
+import type { UnchainedCore } from '@unchainedshop/core';
+import type { Order } from '@unchainedshop/core-orders';
+import DataLoader from 'dataloader';
+
+export default (unchainedAPI: UnchainedCore) =>
+  new DataLoader<{ userId: string; countryCode?: string; orderNumber?: string }, Order | null>(
+    async (queries) => {
+      const userIds = [...new Set(queries.map((q) => q.userId).filter(Boolean))];
+
+      const carts = await unchainedAPI.modules.orders.findCarts({ userIds });
+
+      // findCarts returns carts sorted by `updated` descending, so the first
+      // match per query key is the most recently updated cart, mirroring the
+      // semantics of modules.orders.cart.
+      return queries.map(
+        (q) =>
+          carts.find(
+            (cart) =>
+              cart.userId === q.userId &&
+              (!q.countryCode || cart.countryCode === q.countryCode) &&
+              (!q.orderNumber || cart.orderNumber === q.orderNumber),
+          ) || null,
+      );
+    },
+  );

packages/api/src/loaders/index.ts

@@ -27,6 +27,7 @@ import deliveryProviderLoader from './deliveryProviderLoader.ts';
 import paymentProviderLoader from './paymentProviderLoader.ts';
 import warehousingProviderLoader from './warehousingProviderLoader.ts';
 import orderLoader from './orderLoader.ts';
+import cartLoader from './cartLoader.ts';
 import quotationLoader from './quotationLoader.ts';
 import tokenExportStatusLoader from './tokenExportStatusLoader.ts';
 
@@ -72,6 +73,8 @@ const loaders = (unchainedAPI: UnchainedCore) => {
 
     orderLoader: orderLoader(unchainedAPI),
 
+    cartLoader: cartLoader(unchainedAPI),
+
     quotationLoader: quotationLoader(unchainedAPI),
 
     tokenExportStatusLoader: tokenExportStatusLoader(unchainedAPI),

packages/api/src/resolvers/type/user-types.ts

@@ -168,9 +168,9 @@ export const User: UserHelperTypes = {
   },
 
   async cart(user, params, context) {
-    const { modules, countryCode } = context;
+    const { loaders, countryCode } = context;
     await checkAction(context, viewUserOrders, [user, params]);
-    return modules.orders.cart({
+    return loaders.cartLoader.load({
       countryCode,
       orderNumber: params.orderNumber,
       userId: user._id,

packages/core-orders/src/module/configureOrdersModule-queries.ts

@@ -35,6 +35,36 @@ export interface DateRange {
 
 export type StatisticsDateField = 'created' | 'ordered' | 'rejected' | 'confirmed' | 'fulfilled';
 
+function buildCartSelector({
+  countryCode,
+  orderNumber,
+  userId,
+  userIds,
+}: {
+  countryCode?: string;
+  orderNumber?: string;
+  userId?: string;
+  userIds?: string[];
+}): mongodb.Filter<Order> {
+  const selector: mongodb.Filter<Order> = {
+    status: { $eq: null },
+  };
+
+  if (userIds) {
+    selector.userId = { $in: userIds };
+  } else if (userId) {
+    selector.userId = userId;
+  }
+  if (countryCode) {
+    selector.countryCode = countryCode;
+  }
+  if (orderNumber) {
+    selector.orderNumber = orderNumber;
+  }
+
+  return selector;
+}
+
 function buildDateMatch(dateField: string, dateRange?: DateRange) {
   if (!dateRange?.start && !dateRange?.end) return { [dateField]: { $exists: true } };
 
@@ -70,16 +100,7 @@ export const configureOrdersModuleQueries = ({ Orders }: { Orders: mongodb.Colle
       orderNumber?: string;
       userId: string;
     }) => {
-      const selector: mongodb.Filter<Order> = {
-        countryCode,
-        status: { $eq: null },
-        userId,
-      };
-
-      if (orderNumber) {
-        selector.orderNumber = orderNumber;
-      }
-
+      const selector = buildCartSelector({ countryCode, orderNumber, userId });
       const options: mongodb.FindOptions = {
         sort: {
           updated: -1,
@@ -88,6 +109,29 @@ export const configureOrdersModuleQueries = ({ Orders }: { Orders: mongodb.Colle
       return Orders.findOne(selector, options);
     },
 
+    // Batched variant of `cart`, used by the API cartLoader. Returns the open
+    // carts (status === null) for the given users, most recently updated first.
+    findCarts: async (
+      {
+        countryCode,
+        orderNumber,
+        userId,
+        userIds,
+      }: {
+        countryCode?: string;
+        orderNumber?: string;
+        userId?: string;
+        userIds?: string[];
+      },
+      options?: mongodb.FindOptions,
+    ): Promise<Order[]> => {
+      const selector = buildCartSelector({ countryCode, orderNumber, userId, userIds });
+      return Orders.find(selector, {
+        sort: { updated: -1 },
+        ...options,
+      }).toArray();
+    },
+
     count: async (query: OrderQuery): Promise<number> => {
       const orderCount = await Orders.countDocuments(buildFindSelector(query));
       return orderCount;