feat: perf enhancements

Author: dwene

apps/storefront/app/routes/checkout._index.tsx

@@ -36,26 +36,16 @@ const findCheapestShippingOption = (shippingOptions: StoreCartShippingOption[])
 };
 
 const ensureSelectedCartShippingMethod = async (request: Request, cart: StoreCart) => {
-  const shippingOptions = await fetchShippingOptions(cart.id);
-
   const selectedShippingMethod = cart.shipping_methods?.[0];
 
-  const selectedShippingOption =
-    selectedShippingMethod && shippingOptions.find((option) => option.id === selectedShippingMethod.shipping_option_id);
+  if (selectedShippingMethod) return;
 
-  if (
-    !selectedShippingMethod || // No shipping method has been selected
-    !selectedShippingOption // The selected shipping method is no longer available
-  ) {
-    const cheapestShippingOption = findCheapestShippingOption(shippingOptions);
+  const shippingOptions = await fetchShippingOptions(cart.id);
 
-    if (cheapestShippingOption) {
-      await setShippingMethod(request, { cartId: cart.id, shippingOptionId: cheapestShippingOption.id });
-    }
+  const cheapestShippingOption = findCheapestShippingOption(shippingOptions);
 
-    return;
-  } else if (selectedShippingMethod.amount !== selectedShippingOption.amount) {
-    await setShippingMethod(request, { cartId: cart.id, shippingOptionId: selectedShippingOption.id });
+  if (cheapestShippingOption) {
+    await setShippingMethod(request, { cartId: cart.id, shippingOptionId: cheapestShippingOption.id });
   }
 };
 
@@ -64,9 +54,10 @@ const ensureCartPaymentSessions = async (request: Request, cart: StoreCart) => {
 
   let activeSession = cart.payment_collection?.payment_sessions?.find((session) => session.status === 'pending');
 
-  const paymentProviders = await listCartPaymentProviders(cart.region_id!);
+  if (!activeSession) {
+    const paymentProviders = await listCartPaymentProviders(cart.region_id!);
+    if (!paymentProviders.length) return activeSession;
 
-  if (!activeSession && paymentProviders.length) {
     const provider = paymentProviders.find((p) => p.id !== SYSTEM_PROVIDER_ID) || paymentProviders[0];
 
     const { payment_collection } = await initiatePaymentSession(request, cart, {

apps/storefront/libs/util/server/data/cart.server.ts

@@ -22,6 +22,10 @@ export const retrieveCart = withAuthHeaders(async (request, authHeaders) => {
     });
 });
 
+export const createCart = withAuthHeaders(async (request, authHeaders, data: HttpTypes.StoreCreateCart) => {
+  return await sdk.store.cart.create({ ...data }, {}, authHeaders);
+});
+
 export const getOrCreateCart = withAuthHeaders(async (request, authHeaders) => {
   let cart = await retrieveCart(request);
 
@@ -67,23 +71,25 @@ export const addToCart = withAuthHeaders(
       throw new Error('Missing variant ID when adding to cart');
     }
 
-    const cart = await getOrCreateCart(request);
-
-    if (!cart) {
-      throw new Error('Error retrieving or creating cart');
-    }
+    const cartId = await getCartId(request.headers);
 
-    return await sdk.store.cart
-      .createLineItem(
-        cart.id,
+    if (cartId) {
+      return await sdk.store.cart.createLineItem(
+        cartId,
         {
           variant_id: variantId,
           quantity,
         },
         {},
         authHeaders,
-      )
-      .catch(medusaError);
+      );
+    }
+
+    const region = await getSelectedRegion(request.headers);
+
+    const cart = await createCart(request, { region_id: region.id, items: [{ variant_id: variantId, quantity }] });
+
+    return cart;
   },
 );