Make image, variant, and cart updates faster with useOptimistic (#1365)

2024-07-28 22:58:59 -05:00 · 2024-07-28 22:58:59 -05:00 · 9a4c995bb6
commit 9a4c995bb6
parent dd7449f975
24 changed files with 642 additions and 382 deletions
--- a/app/layout.tsx
+++ b/app/layout.tsx
@ -1,7 +1,12 @@
-import Navbar from 'components/layout/navbar';
+import { CartProvider } from 'components/cart/cart-context';
+import { Navbar } from 'components/layout/navbar';
+import { WelcomeToast } from 'components/welcome-toast';
 import { GeistSans } from 'geist/font/sans';
+import { getCart } from 'lib/shopify';
 import { ensureStartsWith } from 'lib/utils';
+import { cookies } from 'next/headers';
 import { ReactNode } from 'react';
+import { Toaster } from 'sonner';
 import './globals.css';

 const { TWITTER_CREATOR, TWITTER_SITE, SITE_NAME } = process.env;
@ -32,11 +37,21 @@ export const metadata = {
 };

 export default async function RootLayout({ children }: { children: ReactNode }) {
+  const cartId = cookies().get('cartId')?.value;
+  // Don't await the fetch, pass the Promise to the context provider
+  const cart = getCart(cartId);
+
  return (
    <html lang="en" className={GeistSans.variable}>
      <body className="bg-neutral-50 text-black selection:bg-teal-300 dark:bg-neutral-900 dark:text-white dark:selection:bg-pink-500 dark:selection:text-white">
-        <Navbar />
-        <main>{children}</main>
+        <CartProvider cartPromise={cart}>
+          <Navbar />
+          <main>
+            {children}
+            <Toaster closeButton />
+            <WelcomeToast />
+          </main>
+        </CartProvider>
      </body>
    </html>
  );
--- a/app/page.tsx
+++ b/app/page.tsx
@ -9,7 +9,7 @@ export const metadata = {
  }
 };

-export default async function HomePage() {
+export default function HomePage() {
  return (
    <>
      <ThreeItemGrid />
--- a/app/product/[handle]/page.tsx
+++ b/app/product/[handle]/page.tsx
@ -4,6 +4,7 @@ import { notFound } from 'next/navigation';
 import { GridTileImage } from 'components/grid/tile';
 import Footer from 'components/layout/footer';
 import { Gallery } from 'components/product/gallery';
+import { ProductProvider } from 'components/product/product-context';
 import { ProductDescription } from 'components/product/product-description';
 import { HIDDEN_PRODUCT_TAG } from 'lib/constants';
 import { getProduct, getProductRecommendations } from 'lib/shopify';
@ -72,7 +73,7 @@ export default async function ProductPage({ params }: { params: { handle: string
  };

  return (
-    <>
+    <ProductProvider>
      <script
        type="application/ld+json"
        dangerouslySetInnerHTML={{
@ -88,7 +89,7 @@ export default async function ProductPage({ params }: { params: { handle: string
              }
            >
              <Gallery
-                images={product.images.map((image: Image) => ({
+                images={product.images.slice(0, 5).map((image: Image) => ({
                  src: image.url,
                  altText: image.altText
                }))}
@ -97,13 +98,15 @@ export default async function ProductPage({ params }: { params: { handle: string
          </div>

          <div className="basis-full lg:basis-2/6">
-            <ProductDescription product={product} />
+            <Suspense fallback={null}>
+              <ProductDescription product={product} />
+            </Suspense>
          </div>
        </div>
        <RelatedProducts id={product.id} />
      </div>
      <Footer />
-    </>
+    </ProductProvider>
  );
 }

--- a/app/search/loading.tsx
+++ b/app/search/loading.tsx
@ -7,7 +7,7 @@ export default function Loading() {
        .fill(0)
        .map((_, index) => {
          return (
-            <Grid.Item key={index} className="animate-pulse bg-neutral-100 dark:bg-neutral-900" />
+            <Grid.Item key={index} className="animate-pulse bg-neutral-100 dark:bg-neutral-800" />
          );
        })}
    </Grid>
--- a/components/cart/actions.ts
+++ b/components/cart/actions.ts
@ -8,20 +8,9 @@ import { redirect } from 'next/navigation';

 export async function addItem(prevState: any, selectedVariantId: string | undefined) {
  let cartId = cookies().get('cartId')?.value;
-  let cart;

-  if (cartId) {
-    cart = await getCart(cartId);
-  }
-
-  if (!cartId || !cart) {
-    cart = await createCart();
-    cartId = cart.id;
-    cookies().set('cartId', cartId);
-  }
-
-  if (!selectedVariantId) {
-    return 'Missing product variant ID';
+  if (!cartId || !selectedVariantId) {
+    return 'Error adding item to cart';
  }

  try {
@ -32,16 +21,28 @@ export async function addItem(prevState: any, selectedVariantId: string | undefi
  }
 }

-export async function removeItem(prevState: any, lineId: string) {
-  const cartId = cookies().get('cartId')?.value;
+export async function removeItem(prevState: any, merchandiseId: string) {
+  let cartId = cookies().get('cartId')?.value;

  if (!cartId) {
    return 'Missing cart ID';
  }

  try {
-    await removeFromCart(cartId, [lineId]);
-    revalidateTag(TAGS.cart);
+    const cart = await getCart(cartId);
+
+    if (!cart) {
+      return 'Error fetching cart';
+    }
+
+    const lineItem = cart.lines.find((line) => line.merchandise.id === merchandiseId);
+
+    if (lineItem && lineItem.id) {
+      await removeFromCart(cartId, [lineItem.id]);
+      revalidateTag(TAGS.cart);
+    } else {
+      return 'Item not found in cart';
+    }
  } catch (e) {
    return 'Error removing item from cart';
  }
@ -50,40 +51,68 @@ export async function removeItem(prevState: any, lineId: string) {
 export async function updateItemQuantity(
  prevState: any,
  payload: {
-    lineId: string;
-    variantId: string;
+    merchandiseId: string;
    quantity: number;
  }
 ) {
-  const cartId = cookies().get('cartId')?.value;
+  let cartId = cookies().get('cartId')?.value;

  if (!cartId) {
    return 'Missing cart ID';
  }

-  const { lineId, variantId, quantity } = payload;
+  const { merchandiseId, quantity } = payload;

  try {
-    if (quantity === 0) {
-      await removeFromCart(cartId, [lineId]);
-      revalidateTag(TAGS.cart);
-      return;
+    const cart = await getCart(cartId);
+
+    if (!cart) {
+      return 'Error fetching cart';
    }

-    await updateCart(cartId, [
-      {
-        id: lineId,
-        merchandiseId: variantId,
-        quantity
+    const lineItem = cart.lines.find((line) => line.merchandise.id === merchandiseId);
+
+    if (lineItem && lineItem.id) {
+      if (quantity === 0) {
+        await removeFromCart(cartId, [lineItem.id]);
+      } else {
+        await updateCart(cartId, [
+          {
+            id: lineItem.id,
+            merchandiseId,
+            quantity
+          }
+        ]);
      }
-    ]);
+    } else if (quantity > 0) {
+      // If the item doesn't exist in the cart and quantity > 0, add it
+      await addToCart(cartId, [{ merchandiseId, quantity }]);
+    }
+
    revalidateTag(TAGS.cart);
  } catch (e) {
+    console.error(e);
    return 'Error updating item quantity';
  }
 }

-export async function redirectToCheckout(formData: FormData) {
-  const url = formData.get('url') as string;
-  redirect(url);
+export async function redirectToCheckout() {
+  let cartId = cookies().get('cartId')?.value;
+
+  if (!cartId) {
+    return 'Missing cart ID';
+  }
+
+  let cart = await getCart(cartId);
+
+  if (!cart) {
+    return 'Error fetching cart';
+  }
+
+  redirect(cart.checkoutUrl);
+}
+
+export async function createCartAndSetCookie() {
+  let cart = await createCart();
+  cookies().set('cartId', cart.id!);
 }
--- a/components/cart/add-to-cart.tsx
+++ b/components/cart/add-to-cart.tsx
@ -3,10 +3,10 @@
 import { PlusIcon } from '@heroicons/react/24/outline';
 import clsx from 'clsx';
 import { addItem } from 'components/cart/actions';
-import LoadingDots from 'components/loading-dots';
-import { ProductVariant } from 'lib/shopify/types';
-import { useSearchParams } from 'next/navigation';
-import { useFormState, useFormStatus } from 'react-dom';
+import { useProduct } from 'components/product/product-context';
+import { Product, ProductVariant } from 'lib/shopify/types';
+import { useFormState } from 'react-dom';
+import { useCart } from './cart-context';

 function SubmitButton({
  availableForSale,
@ -15,7 +15,6 @@ function SubmitButton({
  availableForSale: boolean;
  selectedVariantId: string | undefined;
 }) {
-  const { pending } = useFormStatus();
  const buttonClasses =
    'relative flex w-full items-center justify-center rounded-full bg-blue-600 p-4 tracking-wide text-white';
  const disabledClasses = 'cursor-not-allowed opacity-60 hover:opacity-60';
@ -45,44 +44,40 @@ function SubmitButton({

  return (
    <button
-      onClick={(e: React.FormEvent<HTMLButtonElement>) => {
-        if (pending) e.preventDefault();
-      }}
      aria-label="Add to cart"
-      aria-disabled={pending}
      className={clsx(buttonClasses, {
-        'hover:opacity-90': true,
-        [disabledClasses]: pending
+        'hover:opacity-90': true
      })}
    >
      <div className="absolute left-0 ml-4">
-        {pending ? <LoadingDots className="mb-3 bg-white" /> : <PlusIcon className="h-5" />}
+        <PlusIcon className="h-5" />
      </div>
      Add To Cart
    </button>
  );
 }

-export function AddToCart({
-  variants,
-  availableForSale
-}: {
-  variants: ProductVariant[];
-  availableForSale: boolean;
-}) {
+export function AddToCart({ product }: { product: Product }) {
+  const { variants, availableForSale } = product;
+  const { addCartItem } = useCart();
+  const { state } = useProduct();
  const [message, formAction] = useFormState(addItem, null);
-  const searchParams = useSearchParams();
-  const defaultVariantId = variants.length === 1 ? variants[0]?.id : undefined;
+
  const variant = variants.find((variant: ProductVariant) =>
-    variant.selectedOptions.every(
-      (option) => option.value === searchParams.get(option.name.toLowerCase())
-    )
+    variant.selectedOptions.every((option) => option.value === state[option.name.toLowerCase()])
  );
+  const defaultVariantId = variants.length === 1 ? variants[0]?.id : undefined;
  const selectedVariantId = variant?.id || defaultVariantId;
  const actionWithVariant = formAction.bind(null, selectedVariantId);
+  const finalVariant = variants.find((variant) => variant.id === selectedVariantId)!;

  return (
-    <form action={actionWithVariant}>
+    <form
+      action={async () => {
+        addCartItem(finalVariant, product);
+        await actionWithVariant();
+      }}
+    >
      <SubmitButton availableForSale={availableForSale} selectedVariantId={selectedVariantId} />
      <p aria-live="polite" className="sr-only" role="status">
        {message}
--- a/components/cart/cart-context.tsx
+++ b/components/cart/cart-context.tsx
@ -0,0 +1,184 @@
+'use client';
+
+import type { Cart, CartItem, Product, ProductVariant } from 'lib/shopify/types';
+import React, { createContext, use, useContext, useMemo, useOptimistic } from 'react';
+
+type UpdateType = 'plus' | 'minus' | 'delete';
+
+type CartAction =
+  | { type: 'UPDATE_ITEM'; payload: { merchandiseId: string; updateType: UpdateType } }
+  | { type: 'ADD_ITEM'; payload: { variant: ProductVariant; product: Product } };
+
+type CartContextType = {
+  cart: Cart | undefined;
+  updateCartItem: (merchandiseId: string, updateType: UpdateType) => void;
+  addCartItem: (variant: ProductVariant, product: Product) => void;
+};
+
+const CartContext = createContext<CartContextType | undefined>(undefined);
+
+function calculateItemCost(quantity: number, price: string): string {
+  return (Number(price) * quantity).toString();
+}
+
+function updateCartItem(item: CartItem, updateType: UpdateType): CartItem | null {
+  if (updateType === 'delete') return null;
+
+  const newQuantity = updateType === 'plus' ? item.quantity + 1 : item.quantity - 1;
+  if (newQuantity === 0) return null;
+
+  const singleItemAmount = Number(item.cost.totalAmount.amount) / item.quantity;
+  const newTotalAmount = calculateItemCost(newQuantity, singleItemAmount.toString());
+
+  return {
+    ...item,
+    quantity: newQuantity,
+    cost: {
+      ...item.cost,
+      totalAmount: {
+        ...item.cost.totalAmount,
+        amount: newTotalAmount
+      }
+    }
+  };
+}
+
+function createOrUpdateCartItem(
+  existingItem: CartItem | undefined,
+  variant: ProductVariant,
+  product: Product
+): CartItem {
+  const quantity = existingItem ? existingItem.quantity + 1 : 1;
+  const totalAmount = calculateItemCost(quantity, variant.price.amount);
+
+  return {
+    id: existingItem?.id,
+    quantity,
+    cost: {
+      totalAmount: {
+        amount: totalAmount,
+        currencyCode: variant.price.currencyCode
+      }
+    },
+    merchandise: {
+      id: variant.id,
+      title: variant.title,
+      selectedOptions: variant.selectedOptions,
+      product: {
+        id: product.id,
+        handle: product.handle,
+        title: product.title,
+        featuredImage: product.featuredImage
+      }
+    }
+  };
+}
+
+function updateCartTotals(lines: CartItem[]): Pick<Cart, 'totalQuantity' | 'cost'> {
+  const totalQuantity = lines.reduce((sum, item) => sum + item.quantity, 0);
+  const totalAmount = lines.reduce((sum, item) => sum + Number(item.cost.totalAmount.amount), 0);
+  const currencyCode = lines[0]?.cost.totalAmount.currencyCode ?? 'USD';
+
+  return {
+    totalQuantity,
+    cost: {
+      subtotalAmount: { amount: totalAmount.toString(), currencyCode },
+      totalAmount: { amount: totalAmount.toString(), currencyCode },
+      totalTaxAmount: { amount: '0', currencyCode }
+    }
+  };
+}
+
+function createEmptyCart(): Cart {
+  return {
+    id: undefined,
+    checkoutUrl: '',
+    totalQuantity: 0,
+    lines: [],
+    cost: {
+      subtotalAmount: { amount: '0', currencyCode: 'USD' },
+      totalAmount: { amount: '0', currencyCode: 'USD' },
+      totalTaxAmount: { amount: '0', currencyCode: 'USD' }
+    }
+  };
+}
+
+function cartReducer(state: Cart | undefined, action: CartAction): Cart {
+  const currentCart = state || createEmptyCart();
+
+  switch (action.type) {
+    case 'UPDATE_ITEM': {
+      const { merchandiseId, updateType } = action.payload;
+      const updatedLines = currentCart.lines
+        .map((item) =>
+          item.merchandise.id === merchandiseId ? updateCartItem(item, updateType) : item
+        )
+        .filter(Boolean) as CartItem[];
+
+      if (updatedLines.length === 0) {
+        return {
+          ...currentCart,
+          lines: [],
+          totalQuantity: 0,
+          cost: {
+            ...currentCart.cost,
+            totalAmount: { ...currentCart.cost.totalAmount, amount: '0' }
+          }
+        };
+      }
+
+      return { ...currentCart, ...updateCartTotals(updatedLines), lines: updatedLines };
+    }
+    case 'ADD_ITEM': {
+      const { variant, product } = action.payload;
+      const existingItem = currentCart.lines.find((item) => item.merchandise.id === variant.id);
+      const updatedItem = createOrUpdateCartItem(existingItem, variant, product);
+
+      const updatedLines = existingItem
+        ? currentCart.lines.map((item) => (item.merchandise.id === variant.id ? updatedItem : item))
+        : [...currentCart.lines, updatedItem];
+
+      return { ...currentCart, ...updateCartTotals(updatedLines), lines: updatedLines };
+    }
+    default:
+      return currentCart;
+  }
+}
+
+export function CartProvider({
+  children,
+  cartPromise
+}: {
+  children: React.ReactNode;
+  cartPromise: Promise<Cart | undefined>;
+}) {
+  const initialCart = use(cartPromise);
+  const [optimisticCart, updateOptimisticCart] = useOptimistic(initialCart, cartReducer);
+
+  const updateCartItem = (merchandiseId: string, updateType: UpdateType) => {
+    updateOptimisticCart({ type: 'UPDATE_ITEM', payload: { merchandiseId, updateType } });
+  };
+
+  const addCartItem = (variant: ProductVariant, product: Product) => {
+    updateOptimisticCart({ type: 'ADD_ITEM', payload: { variant, product } });
+  };
+
+  const value = useMemo(
+    () => ({
+      cart: optimisticCart,
+      updateCartItem,
+      addCartItem
+    }),
+    [optimisticCart]
+  );
+
+  return <CartContext.Provider value={value}>{children}</CartContext.Provider>;
+}
+
+export function useCart() {
+  const context = useContext(CartContext);
+  if (context === undefined) {
+    throw new Error('useCart must be used within a CartProvider');
+  }
+  return context;
+}
--- a/components/cart/delete-item-button.tsx
+++ b/components/cart/delete-item-button.tsx
@ -13,22 +13,22 @@ export function DeleteItemButton({
  optimisticUpdate: any;
 }) {
  const [message, formAction] = useFormState(removeItem, null);
-  const itemId = item.id;
-  const actionWithVariant = formAction.bind(null, itemId);
+  const merchandiseId = item.merchandise.id;
+  const actionWithVariant = formAction.bind(null, merchandiseId);

  return (
    <form
      action={async () => {
-        optimisticUpdate({ itemId, newQuantity: 0, type: 'minus' });
+        optimisticUpdate(merchandiseId, 'delete');
        await actionWithVariant();
      }}
    >
      <button
        type="submit"
        aria-label="Remove cart item"
-        className="ease flex h-[17px] w-[17px] items-center justify-center rounded-full bg-neutral-500 transition-all duration-200"
+        className="flex h-[24px] w-[24px] items-center justify-center rounded-full bg-neutral-500"
      >
-        <XMarkIcon className="hover:text-accent-3 mx-[1px] h-4 w-4 text-white dark:text-black" />
+        <XMarkIcon className="mx-[1px] h-4 w-4 text-white dark:text-black" />
      </button>
      <p aria-live="polite" className="sr-only" role="status">
        {message}
--- a/components/cart/edit-item-quantity-button.tsx
+++ b/components/cart/edit-item-quantity-button.tsx
@ -12,7 +12,7 @@ function SubmitButton({ type }: { type: 'plus' | 'minus' }) {
      type="submit"
      aria-label={type === 'plus' ? 'Increase item quantity' : 'Reduce item quantity'}
      className={clsx(
-        'ease flex h-full min-w-[36px] max-w-[36px] flex-none items-center justify-center rounded-full px-2 transition-all duration-200 hover:border-neutral-800 hover:opacity-80',
+        'ease flex h-full min-w-[36px] max-w-[36px] flex-none items-center justify-center rounded-full p-2 transition-all duration-200 hover:border-neutral-800 hover:opacity-80',
        {
          'ml-auto': type === 'minus'
        }
@ -38,8 +38,7 @@ export function EditItemQuantityButton({
 }) {
  const [message, formAction] = useFormState(updateItemQuantity, null);
  const payload = {
-    lineId: item.id,
-    variantId: item.merchandise.id,
+    merchandiseId: item.merchandise.id,
    quantity: type === 'plus' ? item.quantity + 1 : item.quantity - 1
  };
  const actionWithVariant = formAction.bind(null, payload);
@ -47,7 +46,7 @@ export function EditItemQuantityButton({
  return (
    <form
      action={async () => {
-        optimisticUpdate({ itemId: payload.lineId, newQuantity: payload.quantity, type });
+        optimisticUpdate(payload.merchandiseId, type);
        await actionWithVariant();
      }}
    >
--- a/components/cart/index.tsx
+++ b/components/cart/index.tsx
@ -1,14 +0,0 @@
-import { getCart } from 'lib/shopify';
-import { cookies } from 'next/headers';
-import CartModal from './modal';
-
-export default async function Cart() {
-  const cartId = cookies().get('cartId')?.value;
-  let cart;
-
-  if (cartId) {
-    cart = await getCart(cartId);
-  }
-
-  return <CartModal cart={cart} />;
-}
--- a/components/cart/modal.tsx
+++ b/components/cart/modal.tsx
@ -5,13 +5,13 @@ import { ShoppingCartIcon } from '@heroicons/react/24/outline';
 import LoadingDots from 'components/loading-dots';
 import Price from 'components/price';
 import { DEFAULT_OPTION } from 'lib/constants';
-import type { Cart, CartItem } from 'lib/shopify/types';
 import { createUrl } from 'lib/utils';
 import Image from 'next/image';
 import Link from 'next/link';
-import { Fragment, useEffect, useOptimistic, useRef, useState } from 'react';
+import { Fragment, useEffect, useRef, useState } from 'react';
 import { useFormStatus } from 'react-dom';
-import { redirectToCheckout } from './actions';
+import { createCartAndSetCookie, redirectToCheckout } from './actions';
+import { useCart } from './cart-context';
 import CloseCart from './close-cart';
 import { DeleteItemButton } from './delete-item-button';
 import { EditItemQuantityButton } from './edit-item-quantity-button';
@ -21,96 +21,28 @@ type MerchandiseSearchParams = {
  [key: string]: string;
 };

-type NewState = {
-  itemId: string;
-  newQuantity: number;
-  type: 'plus' | 'minus';
-};
-
-function reducer(state: Cart | undefined, newState: NewState) {
-  if (!state) {
-    return state;
-  }
-
-  let updatedLines = state.lines
-    .map((item: CartItem) => {
-      if (item.id === newState.itemId) {
-        if (newState.type === 'minus' && newState.newQuantity === 0) {
-          // Remove the item if quantity becomes 0
-          return null;
-        }
-
-        const singleItemAmount = Number(item.cost.totalAmount.amount) / item.quantity;
-        const newTotalAmount = singleItemAmount * newState.newQuantity;
-
-        return {
-          ...item,
-          quantity: newState.newQuantity,
-          cost: {
-            ...item.cost,
-            totalAmount: {
-              ...item.cost.totalAmount,
-              amount: newTotalAmount.toString()
-            }
-          }
-        };
-      }
-      return item;
-    })
-    .filter(Boolean) as CartItem[];
-
-  const newTotalQuantity = updatedLines.reduce((sum, item) => sum + item.quantity, 0);
-  const newTotalAmount = updatedLines.reduce(
-    (sum, item) => sum + Number(item.cost.totalAmount.amount),
-    0
-  );
-
-  // If there are no items left, return an empty cart
-  if (updatedLines.length === 0) {
-    return {
-      ...state,
-      lines: [],
-      totalQuantity: 0,
-      cost: {
-        ...state.cost,
-        totalAmount: {
-          ...state.cost.totalAmount,
-          amount: '0'
-        }
-      }
-    };
-  }
-
-  return {
-    ...state,
-    lines: updatedLines,
-    totalQuantity: newTotalQuantity,
-    cost: {
-      ...state.cost,
-      totalAmount: {
-        ...state.cost.totalAmount,
-        amount: newTotalAmount.toString()
-      }
-    }
-  };
-}
-
-export default function CartModal({ cart: initialCart }: { cart: Cart | undefined }) {
+export default function CartModal() {
+  const { cart, updateCartItem } = useCart();
  const [isOpen, setIsOpen] = useState(false);
-  const [cart, updateCartItem] = useOptimistic(initialCart, reducer);
  const quantityRef = useRef(cart?.totalQuantity);
  const openCart = () => setIsOpen(true);
  const closeCart = () => setIsOpen(false);

  useEffect(() => {
-    // Open cart modal when quantity changes.
-    if (cart?.totalQuantity !== quantityRef.current) {
-      // But only if it's not already open (quantity also changes when editing items in cart).
+    if (!cart) {
+      createCartAndSetCookie();
+    }
+  }, [cart]);
+
+  useEffect(() => {
+    if (
+      cart?.totalQuantity &&
+      cart?.totalQuantity !== quantityRef.current &&
+      cart?.totalQuantity > 0
+    ) {
      if (!isOpen) {
        setIsOpen(true);
      }
-
-      // Always update the quantity reference
      quantityRef.current = cart?.totalQuantity;
    }
  }, [isOpen, cart?.totalQuantity, quantityRef]);
@ -158,84 +90,89 @@ export default function CartModal({ cart: initialCart }: { cart: Cart | undefine
              ) : (
                <div className="flex h-full flex-col justify-between overflow-hidden p-1">
                  <ul className="flex-grow overflow-auto py-4">
-                    {cart.lines.map((item, i) => {
-                      const merchandiseSearchParams = {} as MerchandiseSearchParams;
+                    {cart.lines
+                      .sort((a, b) =>
+                        a.merchandise.product.title.localeCompare(b.merchandise.product.title)
+                      )
+                      .map((item, i) => {
+                        const merchandiseSearchParams = {} as MerchandiseSearchParams;

-                      item.merchandise.selectedOptions.forEach(({ name, value }) => {
-                        if (value !== DEFAULT_OPTION) {
-                          merchandiseSearchParams[name.toLowerCase()] = value;
-                        }
-                      });
+                        item.merchandise.selectedOptions.forEach(({ name, value }) => {
+                          if (value !== DEFAULT_OPTION) {
+                            merchandiseSearchParams[name.toLowerCase()] = value;
+                          }
+                        });

-                      const merchandiseUrl = createUrl(
-                        `/product/${item.merchandise.product.handle}`,
-                        new URLSearchParams(merchandiseSearchParams)
-                      );
+                        const merchandiseUrl = createUrl(
+                          `/product/${item.merchandise.product.handle}`,
+                          new URLSearchParams(merchandiseSearchParams)
+                        );

-                      return (
-                        <li
-                          key={i}
-                          className="flex w-full flex-col border-b border-neutral-300 dark:border-neutral-700"
-                        >
-                          <div className="relative flex w-full flex-row justify-between px-1 py-4">
-                            <div className="absolute z-40 -mt-2 ml-[55px]">
-                              <DeleteItemButton item={item} optimisticUpdate={updateCartItem} />
-                            </div>
-                            <Link
-                              href={merchandiseUrl}
-                              onClick={closeCart}
-                              className="z-30 flex flex-row space-x-4"
-                            >
-                              <div className="relative h-16 w-16 cursor-pointer overflow-hidden rounded-md border border-neutral-300 bg-neutral-300 dark:border-neutral-700 dark:bg-neutral-900 dark:hover:bg-neutral-800">
-                                <Image
-                                  className="h-full w-full object-cover"
-                                  width={64}
-                                  height={64}
-                                  alt={
-                                    item.merchandise.product.featuredImage.altText ||
-                                    item.merchandise.product.title
-                                  }
-                                  src={item.merchandise.product.featuredImage.url}
-                                />
+                        return (
+                          <li
+                            key={i}
+                            className="flex w-full flex-col border-b border-neutral-300 dark:border-neutral-700"
+                          >
+                            <div className="relative flex w-full flex-row justify-between px-1 py-4">
+                              <div className="absolute z-40 -ml-1 -mt-2">
+                                <DeleteItemButton item={item} optimisticUpdate={updateCartItem} />
                              </div>
-
-                              <div className="flex flex-1 flex-col text-base">
-                                <span className="leading-tight">
-                                  {item.merchandise.product.title}
-                                </span>
-                                {item.merchandise.title !== DEFAULT_OPTION ? (
-                                  <p className="text-sm text-neutral-500 dark:text-neutral-400">
-                                    {item.merchandise.title}
+                              <div className="flex flex-row">
+                                <div className="relative h-16 w-16 overflow-hidden rounded-md border border-neutral-300 bg-neutral-300 dark:border-neutral-700 dark:bg-neutral-900 dark:hover:bg-neutral-800">
+                                  <Image
+                                    className="h-full w-full object-cover"
+                                    width={64}
+                                    height={64}
+                                    alt={
+                                      item.merchandise.product.featuredImage.altText ||
+                                      item.merchandise.product.title
+                                    }
+                                    src={item.merchandise.product.featuredImage.url}
+                                  />
+                                </div>
+                                <Link
+                                  href={merchandiseUrl}
+                                  onClick={closeCart}
+                                  className="z-30 ml-2 flex flex-row space-x-4"
+                                >
+                                  <div className="flex flex-1 flex-col text-base">
+                                    <span className="leading-tight">
+                                      {item.merchandise.product.title}
+                                    </span>
+                                    {item.merchandise.title !== DEFAULT_OPTION ? (
+                                      <p className="text-sm text-neutral-500 dark:text-neutral-400">
+                                        {item.merchandise.title}
+                                      </p>
+                                    ) : null}
+                                  </div>
+                                </Link>
+                              </div>
+                              <div className="flex h-16 flex-col justify-between">
+                                <Price
+                                  className="flex justify-end space-y-2 text-right text-sm"
+                                  amount={item.cost.totalAmount.amount}
+                                  currencyCode={item.cost.totalAmount.currencyCode}
+                                />
+                                <div className="ml-auto flex h-9 flex-row items-center rounded-full border border-neutral-200 dark:border-neutral-700">
+                                  <EditItemQuantityButton
+                                    item={item}
+                                    type="minus"
+                                    optimisticUpdate={updateCartItem}
+                                  />
+                                  <p className="w-6 text-center">
+                                    <span className="w-full text-sm">{item.quantity}</span>
                                  </p>
-                                ) : null}
-                              </div>
-                            </Link>
-                            <div className="flex h-16 flex-col justify-between">
-                              <Price
-                                className="flex justify-end space-y-2 text-right text-sm"
-                                amount={item.cost.totalAmount.amount}
-                                currencyCode={item.cost.totalAmount.currencyCode}
-                              />
-                              <div className="ml-auto flex h-9 flex-row items-center rounded-full border border-neutral-200 dark:border-neutral-700">
-                                <EditItemQuantityButton
-                                  item={item}
-                                  type="minus"
-                                  optimisticUpdate={updateCartItem}
-                                />
-                                <p className="w-6 text-center">
-                                  <span className="w-full text-sm">{item.quantity}</span>
-                                </p>
-                                <EditItemQuantityButton
-                                  item={item}
-                                  type="plus"
-                                  optimisticUpdate={updateCartItem}
-                                />
+                                  <EditItemQuantityButton
+                                    item={item}
+                                    type="plus"
+                                    optimisticUpdate={updateCartItem}
+                                  />
+                                </div>
                              </div>
                            </div>
-                          </div>
-                        </li>
-                      );
-                    })}
+                          </li>
+                        );
+                      })}
                  </ul>
                  <div className="py-4 text-sm text-neutral-500 dark:text-neutral-400">
                    <div className="mb-3 flex items-center justify-between border-b border-neutral-200 pb-1 dark:border-neutral-700">
@ -260,7 +197,7 @@ export default function CartModal({ cart: initialCart }: { cart: Cart | undefine
                    </div>
                  </div>
                  <form action={redirectToCheckout}>
-                    <CheckoutButton cart={cart} />
+                    <CheckoutButton />
                  </form>
                </div>
              )}
@ -272,19 +209,16 @@ export default function CartModal({ cart: initialCart }: { cart: Cart | undefine
  );
 }

-function CheckoutButton({ cart }: { cart: Cart }) {
+function CheckoutButton() {
  const { pending } = useFormStatus();

  return (
-    <>
-      <input type="hidden" name="url" value={cart.checkoutUrl} />
-      <button
-        className="block w-full rounded-full bg-blue-600 p-3 text-center text-sm font-medium text-white opacity-90 hover:opacity-100"
-        type="submit"
-        disabled={pending}
-      >
-        {pending ? <LoadingDots className="bg-white" /> : 'Proceed to Checkout'}
-      </button>
-    </>
+    <button
+      className="block w-full rounded-full bg-blue-600 p-3 text-center text-sm font-medium text-white opacity-90 hover:opacity-100"
+      type="submit"
+      disabled={pending}
+    >
+      {pending ? <LoadingDots className="bg-white" /> : 'Proceed to Checkout'}
+    </button>
  );
 }
--- a/components/layout/footer.tsx
+++ b/components/layout/footer.tsx
@ -56,10 +56,12 @@ export default async function Footer() {
            {copyrightName.length && !copyrightName.endsWith('.') ? '.' : ''} All rights reserved.
          </p>
          <hr className="mx-4 hidden h-4 w-[1px] border-l border-neutral-400 md:inline-block" />
-          <p>Designed in California</p>
+          <p>
+            <a href="https://github.com/vercel/commerce">View the source</a>
+          </p>
          <p className="md:ml-auto">
            <a href="https://vercel.com" className="text-black dark:text-white">
-              Crafted by ▲ Vercel
+              Created by ▲ Vercel
            </a>
          </p>
        </div>
--- a/components/layout/navbar/index.tsx
+++ b/components/layout/navbar/index.tsx
@ -1,5 +1,4 @@
-import Cart from 'components/cart';
-import OpenCart from 'components/cart/open-cart';
+import CartModal from 'components/cart/modal';
 import LogoSquare from 'components/logo-square';
 import { getMenu } from 'lib/shopify';
 import { Menu } from 'lib/shopify/types';
@ -7,9 +6,10 @@ import Link from 'next/link';
 import { Suspense } from 'react';
 import MobileMenu from './mobile-menu';
 import Search, { SearchSkeleton } from './search';
+
 const { SITE_NAME } = process.env;

-export default async function Navbar() {
+export async function Navbar() {
  const menu = await getMenu('next-js-frontend-header-menu');

  return (
@ -53,9 +53,7 @@ export default async function Navbar() {
          </Suspense>
        </div>
        <div className="flex justify-end md:w-1/3">
-          <Suspense fallback={<OpenCart />}>
-            <Cart />
-          </Suspense>
+          <CartModal />
        </div>
      </div>
    </nav>
--- a/components/layout/navbar/search.tsx
+++ b/components/layout/navbar/search.tsx
@ -33,7 +33,7 @@ export default function Search() {
        placeholder="Search for products..."
        autoComplete="off"
        defaultValue={searchParams?.get('q') || ''}
-        className="w-full rounded-lg border bg-white px-4 py-2 text-sm text-black placeholder:text-neutral-500 dark:border-neutral-800 dark:bg-transparent dark:text-white dark:placeholder:text-neutral-400"
+        className="text-md w-full rounded-lg border bg-white px-4 py-2 text-black placeholder:text-neutral-500 md:text-sm dark:border-neutral-800 dark:bg-transparent dark:text-white dark:placeholder:text-neutral-400"
      />
      <div className="absolute right-0 top-0 mr-3 flex h-full items-center">
        <MagnifyingGlassIcon className="h-4" />
--- a/components/product/gallery.tsx
+++ b/components/product/gallery.tsx
@ -2,32 +2,22 @@

 import { ArrowLeftIcon, ArrowRightIcon } from '@heroicons/react/24/outline';
 import { GridTileImage } from 'components/grid/tile';
-import { createUrl } from 'lib/utils';
+import { useProduct, useUpdateURL } from 'components/product/product-context';
 import Image from 'next/image';
-import Link from 'next/link';
-import { usePathname, useSearchParams } from 'next/navigation';

 export function Gallery({ images }: { images: { src: string; altText: string }[] }) {
-  const pathname = usePathname();
-  const searchParams = useSearchParams();
-  const imageSearchParam = searchParams.get('image');
-  const imageIndex = imageSearchParam ? parseInt(imageSearchParam) : 0;
+  const { state, updateImage } = useProduct();
+  const updateURL = useUpdateURL();
+  const imageIndex = state.image ? parseInt(state.image) : 0;

-  const nextSearchParams = new URLSearchParams(searchParams.toString());
  const nextImageIndex = imageIndex + 1 < images.length ? imageIndex + 1 : 0;
-  nextSearchParams.set('image', nextImageIndex.toString());
-  const nextUrl = createUrl(pathname, nextSearchParams);
-
-  const previousSearchParams = new URLSearchParams(searchParams.toString());
  const previousImageIndex = imageIndex === 0 ? images.length - 1 : imageIndex - 1;
-  previousSearchParams.set('image', previousImageIndex.toString());
-  const previousUrl = createUrl(pathname, previousSearchParams);

  const buttonClassName =
    'h-full px-6 transition-all ease-in-out hover:scale-110 hover:text-black dark:hover:text-white flex items-center justify-center';

  return (
-    <>
+    <form>
      <div className="relative aspect-square h-full max-h-[550px] w-full overflow-hidden">
        {images[imageIndex] && (
          <Image
@ -43,23 +33,27 @@ export function Gallery({ images }: { images: { src: string; altText: string }[]
        {images.length > 1 ? (
          <div className="absolute bottom-[15%] flex w-full justify-center">
            <div className="mx-auto flex h-11 items-center rounded-full border border-white bg-neutral-50/80 text-neutral-500 backdrop-blur dark:border-black dark:bg-neutral-900/80">
-              <Link
+              <button
+                formAction={() => {
+                  const newState = updateImage(previousImageIndex.toString());
+                  updateURL(newState);
+                }}
                aria-label="Previous product image"
-                href={previousUrl}
                className={buttonClassName}
-                scroll={false}
              >
                <ArrowLeftIcon className="h-5" />
-              </Link>
+              </button>
              <div className="mx-1 h-6 w-px bg-neutral-500"></div>
-              <Link
+              <button
+                formAction={() => {
+                  const newState = updateImage(nextImageIndex.toString());
+                  updateURL(newState);
+                }}
                aria-label="Next product image"
-                href={nextUrl}
                className={buttonClassName}
-                scroll={false}
              >
                <ArrowRightIcon className="h-5" />
-              </Link>
+              </button>
            </div>
          </div>
        ) : null}
@ -69,16 +63,15 @@ export function Gallery({ images }: { images: { src: string; altText: string }[]
        <ul className="my-12 flex items-center justify-center gap-2 overflow-auto py-1 lg:mb-0">
          {images.map((image, index) => {
            const isActive = index === imageIndex;
-            const imageSearchParams = new URLSearchParams(searchParams.toString());
-
-            imageSearchParams.set('image', index.toString());

            return (
              <li key={image.src} className="h-20 w-20">
-                <Link
-                  aria-label="Enlarge product image"
-                  href={createUrl(pathname, imageSearchParams)}
-                  scroll={false}
+                <button
+                  formAction={() => {
+                    const newState = updateImage(index.toString());
+                    updateURL(newState);
+                  }}
+                  aria-label="Select product image"
                  className="h-full w-full"
                >
                  <GridTileImage
@ -88,12 +81,12 @@ export function Gallery({ images }: { images: { src: string; altText: string }[]
                    height={80}
                    active={isActive}
                  />
-                </Link>
+                </button>
              </li>
            );
          })}
        </ul>
      ) : null}
-    </>
+    </form>
  );
 }
--- a/components/product/product-context.tsx
+++ b/components/product/product-context.tsx
@ -0,0 +1,81 @@
+'use client';
+
+import { useRouter, useSearchParams } from 'next/navigation';
+import React, { createContext, useContext, useMemo, useOptimistic } from 'react';
+
+type ProductState = {
+  [key: string]: string;
+} & {
+  image?: string;
+};
+
+type ProductContextType = {
+  state: ProductState;
+  updateOption: (name: string, value: string) => ProductState;
+  updateImage: (index: string) => ProductState;
+};
+
+const ProductContext = createContext<ProductContextType | undefined>(undefined);
+
+export function ProductProvider({ children }: { children: React.ReactNode }) {
+  const searchParams = useSearchParams();
+
+  const getInitialState = () => {
+    const params: ProductState = {};
+    for (const [key, value] of searchParams.entries()) {
+      params[key] = value;
+    }
+    return params;
+  };
+
+  const [state, setOptimisticState] = useOptimistic(
+    getInitialState(),
+    (prevState: ProductState, update: ProductState) => ({
+      ...prevState,
+      ...update
+    })
+  );
+
+  const updateOption = (name: string, value: string) => {
+    const newState = { [name]: value };
+    setOptimisticState(newState);
+    return { ...state, ...newState };
+  };
+
+  const updateImage = (index: string) => {
+    const newState = { image: index };
+    setOptimisticState(newState);
+    return { ...state, ...newState };
+  };
+
+  const value = useMemo(
+    () => ({
+      state,
+      updateOption,
+      updateImage
+    }),
+    [state]
+  );
+
+  return <ProductContext.Provider value={value}>{children}</ProductContext.Provider>;
+}
+
+export function useProduct() {
+  const context = useContext(ProductContext);
+  if (context === undefined) {
+    throw new Error('useProduct must be used within a ProductProvider');
+  }
+  return context;
+}
+
+export function useUpdateURL() {
+  const router = useRouter();
+
+  return (state: ProductState) => {
+    const newParams = new URLSearchParams(window.location.search);
+    Object.entries(state).forEach(([key, value]) => {
+      newParams.set(key, value);
+    });
+    router.push(`?${newParams.toString()}`, { scroll: false });
+  };
+}
--- a/components/product/product-description.tsx
+++ b/components/product/product-description.tsx
@ -2,7 +2,6 @@ import { AddToCart } from 'components/cart/add-to-cart';
 import Price from 'components/price';
 import Prose from 'components/prose';
 import { Product } from 'lib/shopify/types';
-import { Suspense } from 'react';
 import { VariantSelector } from './variant-selector';

 export function ProductDescription({ product }: { product: Product }) {
@ -17,20 +16,14 @@ export function ProductDescription({ product }: { product: Product }) {
          />
        </div>
      </div>
-      <Suspense fallback={null}>
-        <VariantSelector options={product.options} variants={product.variants} />
-      </Suspense>
-
+      <VariantSelector options={product.options} variants={product.variants} />
      {product.descriptionHtml ? (
        <Prose
          className="mb-6 text-sm leading-tight dark:text-white/[60%]"
          html={product.descriptionHtml}
        />
      ) : null}
-
-      <Suspense fallback={null}>
-        <AddToCart variants={product.variants} availableForSale={product.availableForSale} />
-      </Suspense>
+      <AddToCart product={product} />
    </>
  );
 }
--- a/components/product/variant-selector.tsx
+++ b/components/product/variant-selector.tsx
@ -1,14 +1,13 @@
 'use client';

 import clsx from 'clsx';
+import { useProduct, useUpdateURL } from 'components/product/product-context';
 import { ProductOption, ProductVariant } from 'lib/shopify/types';
-import { createUrl } from 'lib/utils';
-import { usePathname, useRouter, useSearchParams } from 'next/navigation';

 type Combination = {
  id: string;
  availableForSale: boolean;
-  [key: string]: string | boolean; // ie. { color: 'Red', size: 'Large', ... }
+  [key: string]: string | boolean;
 };

 export function VariantSelector({
@ -18,9 +17,8 @@ export function VariantSelector({
  options: ProductOption[];
  variants: ProductVariant[];
 }) {
-  const router = useRouter();
-  const pathname = usePathname();
-  const searchParams = useSearchParams();
+  const { state, updateOption } = useProduct();
+  const updateURL = useUpdateURL();
  const hasNoOptionsOrJustOneOption =
    !options.length || (options.length === 1 && options[0]?.values.length === 1);

@ -31,7 +29,6 @@ export function VariantSelector({
  const combinations: Combination[] = variants.map((variant) => ({
    id: variant.id,
    availableForSale: variant.availableForSale,
-    // Adds key / value pairs for each variant (ie. "color": "Black" and "size": 'M").
    ...variant.selectedOptions.reduce(
      (accumulator, option) => ({ ...accumulator, [option.name.toLowerCase()]: option.value }),
      {}
@ -39,68 +36,58 @@ export function VariantSelector({
  }));

  return options.map((option) => (
-    <dl className="mb-8" key={option.id}>
-      <dt className="mb-4 text-sm uppercase tracking-wide">{option.name}</dt>
-      <dd className="flex flex-wrap gap-3">
-        {option.values.map((value) => {
-          const optionNameLowerCase = option.name.toLowerCase();
+    <form key={option.id}>
+      <dl className="mb-8">
+        <dt className="mb-4 text-sm uppercase tracking-wide">{option.name}</dt>
+        <dd className="flex flex-wrap gap-3">
+          {option.values.map((value) => {
+            const optionNameLowerCase = option.name.toLowerCase();

-          // Base option params on current params so we can preserve any other param state in the url.
-          const optionSearchParams = new URLSearchParams(searchParams.toString());
+            // Base option params on current selectedOptions so we can preserve any other param state.
+            const optionParams = { ...state, [optionNameLowerCase]: value };

-          // Update the option params using the current option to reflect how the url *would* change,
-          // if the option was clicked.
-          optionSearchParams.set(optionNameLowerCase, value);
-          const optionUrl = createUrl(pathname, optionSearchParams);
+            // Filter out invalid options and check if the option combination is available for sale.
+            const filtered = Object.entries(optionParams).filter(([key, value]) =>
+              options.find(
+                (option) => option.name.toLowerCase() === key && option.values.includes(value)
+              )
+            );
+            const isAvailableForSale = combinations.find((combination) =>
+              filtered.every(
+                ([key, value]) => combination[key] === value && combination.availableForSale
+              )
+            );

-          // In order to determine if an option is available for sale, we need to:
-          //
-          // 1. Filter out all other param state
-          // 2. Filter out invalid options
-          // 3. Check if the option combination is available for sale
-          //
-          // This is the "magic" that will cross check possible variant combinations and preemptively
-          // disable combinations that are not available. For example, if the color gray is only available in size medium,
-          // then all other sizes should be disabled.
-          const filtered = Array.from(optionSearchParams.entries()).filter(([key, value]) =>
-            options.find(
-              (option) => option.name.toLowerCase() === key && option.values.includes(value)
-            )
-          );
-          const isAvailableForSale = combinations.find((combination) =>
-            filtered.every(
-              ([key, value]) => combination[key] === value && combination.availableForSale
-            )
-          );
+            // The option is active if it's in the selected options.
+            const isActive = state[optionNameLowerCase] === value;

-          // The option is active if it's in the url params.
-          const isActive = searchParams.get(optionNameLowerCase) === value;
-
-          return (
-            <button
-              key={value}
-              aria-disabled={!isAvailableForSale}
-              disabled={!isAvailableForSale}
-              onClick={() => {
-                router.replace(optionUrl, { scroll: false });
-              }}
-              title={`${option.name} ${value}${!isAvailableForSale ? ' (Out of Stock)' : ''}`}
-              className={clsx(
-                'flex min-w-[48px] items-center justify-center rounded-full border bg-neutral-100 px-2 py-1 text-sm dark:border-neutral-800 dark:bg-neutral-900',
-                {
-                  'cursor-default ring-2 ring-blue-600': isActive,
-                  'ring-1 ring-transparent transition duration-300 ease-in-out hover:scale-110 hover:ring-blue-600 ':
-                    !isActive && isAvailableForSale,
-                  'relative z-10 cursor-not-allowed overflow-hidden bg-neutral-100 text-neutral-500 ring-1 ring-neutral-300 before:absolute before:inset-x-0 before:-z-10 before:h-px before:-rotate-45 before:bg-neutral-300 before:transition-transform dark:bg-neutral-900 dark:text-neutral-400 dark:ring-neutral-700 before:dark:bg-neutral-700':
-                    !isAvailableForSale
-                }
-              )}
-            >
-              {value}
-            </button>
-          );
-        })}
-      </dd>
-    </dl>
+            return (
+              <button
+                formAction={() => {
+                  const newState = updateOption(optionNameLowerCase, value);
+                  updateURL(newState);
+                }}
+                key={value}
+                aria-disabled={!isAvailableForSale}
+                disabled={!isAvailableForSale}
+                title={`${option.name} ${value}${!isAvailableForSale ? ' (Out of Stock)' : ''}`}
+                className={clsx(
+                  'flex min-w-[48px] items-center justify-center rounded-full border bg-neutral-100 px-2 py-1 text-sm dark:border-neutral-800 dark:bg-neutral-900',
+                  {
+                    'cursor-default ring-2 ring-blue-600': isActive,
+                    'ring-1 ring-transparent transition duration-300 ease-in-out hover:ring-blue-600':
+                      !isActive && isAvailableForSale,
+                    'relative z-10 cursor-not-allowed overflow-hidden bg-neutral-100 text-neutral-500 ring-1 ring-neutral-300 before:absolute before:inset-x-0 before:-z-10 before:h-px before:-rotate-45 before:bg-neutral-300 before:transition-transform dark:bg-neutral-900 dark:text-neutral-400 dark:ring-neutral-700 before:dark:bg-neutral-700':
+                      !isAvailableForSale
+                  }
+                )}
+              >
+                {value}
+              </button>
+            );
+          })}
+        </dd>
+      </dl>
+    </form>
  ));
 }
--- a/components/welcome-toast.tsx
+++ b/components/welcome-toast.tsx
@ -0,0 +1,35 @@
+'use client';
+
+import { useEffect } from 'react';
+import { toast } from 'sonner';
+
+export function WelcomeToast() {
+  useEffect(() => {
+    // ignore if screen height is too small
+    if (window.innerHeight < 650) return;
+    if (!document.cookie.includes('welcome-toast=2')) {
+      toast('🛍️ Welcome to Next.js Commerce!', {
+        id: 'welcome-toast',
+        duration: Infinity,
+        onDismiss: () => {
+          document.cookie = 'welcome-toast=2; max-age=31536000; path=/';
+        },
+        description: (
+          <>
+            This is a high-performance, SSR storefront powered by Shopify, Next.js, and Vercel.{' '}
+            <a
+              href="https://vercel.com/templates/next.js/nextjs-commerce"
+              className="text-blue-600 hover:underline"
+              target="_blank"
+            >
+              Deploy your own
+            </a>
+            .
+          </>
+        )
+      });
+    }
+  }, []);
+
+  return null;
+}
--- a/lib/shopify/index.ts
+++ b/lib/shopify/index.ts
@ -254,12 +254,15 @@ export async function updateCart(
  return reshapeCart(res.body.data.cartLinesUpdate.cart);
 }

-export async function getCart(cartId: string): Promise<Cart | undefined> {
+export async function getCart(cartId: string | undefined): Promise<Cart | undefined> {
+  if (!cartId) {
+    return undefined;
+  }
+
  const res = await shopifyFetch<ShopifyCartOperation>({
    query: getCartQuery,
    variables: { cartId },
-    tags: [TAGS.cart],
-    cache: 'no-store'
+    tags: [TAGS.cart]
  });

  // Old carts becomes `null` when you checkout.
--- a/lib/shopify/types.ts
+++ b/lib/shopify/types.ts
@ -12,8 +12,15 @@ export type Cart = Omit<ShopifyCart, 'lines'> & {
  lines: CartItem[];
 };

-export type CartItem = {
+export type CartProduct = {
  id: string;
+  handle: string;
+  title: string;
+  featuredImage: Image;
+};
+
+export type CartItem = {
+  id: string | undefined;
  quantity: number;
  cost: {
    totalAmount: Money;
@ -25,7 +32,7 @@ export type CartItem = {
      name: string;
      value: string;
    }[];
-    product: Product;
+    product: CartProduct;
  };
 };

@ -89,7 +96,7 @@ export type SEO = {
 };

 export type ShopifyCart = {
-  id: string;
+  id: string | undefined;
  checkoutUrl: string;
  cost: {
    subtotalAmount: Money;
--- a/package.json
+++ b/package.json
@ -19,7 +19,8 @@
    "geist": "^1.3.1",
    "next": "14.2.5",
    "react": "18.3.1",
-    "react-dom": "18.3.1"
+    "react-dom": "18.3.1",
+    "sonner": "^1.5.0"
  },
  "devDependencies": {
    "@tailwindcss/container-queries": "^0.1.1",
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@ -29,6 +29,9 @@ importers:
      react-dom:
        specifier: 18.3.1
        version: 18.3.1(react@18.3.1)
+      sonner:
+        specifier: ^1.5.0
+        version: 1.5.0(react-dom@18.3.1(react@18.3.1))(react@18.3.1)
    devDependencies:
      '@tailwindcss/container-queries':
        specifier: ^0.1.1
@ -749,6 +752,12 @@ packages:
    resolution: {integrity: sha512-bzyZ1e88w9O1iNJbKnOlvYTrWPDl46O1bG0D3XInv+9tkPrxrN8jUUTiFlDkkmKWgn1M6CfIA13SuGqOa9Korw==}
    engines: {node: '>=14'}

+  sonner@1.5.0:
+    resolution: {integrity: sha512-FBjhG/gnnbN6FY0jaNnqZOMmB73R+5IiyYAw8yBj7L54ER7HB3fOSE5OFiQiE2iXWxeXKvg6fIP4LtVppHEdJA==}
+    peerDependencies:
+      react: ^18.0.0
+      react-dom: ^18.0.0
+
  source-map-js@1.2.0:
    resolution: {integrity: sha512-itJW8lvSA0TXEphiRoawsCksnlf8SyvmFzIhltqAHluXd88pkCd+cXJVHTDwdCr0IzwptSm035IHQktUu1QUMg==}
    engines: {node: '>=0.10.0'}
@ -1435,6 +1444,11 @@ snapshots:

  signal-exit@4.1.0: {}

+  sonner@1.5.0(react-dom@18.3.1(react@18.3.1))(react@18.3.1):
+    dependencies:
+      react: 18.3.1
+      react-dom: 18.3.1(react@18.3.1)
+
  source-map-js@1.2.0: {}

  streamsearch@1.1.0: {}
--- a/tsconfig.json
+++ b/tsconfig.json
@ -1,7 +1,8 @@
 {
  "compilerOptions": {
-    "target": "es5",
+    "target": "es2015",
    "lib": ["dom", "dom.iterable", "esnext"],
+    "downlevelIteration": true,
    "allowJs": true,
    "skipLibCheck": true,
    "strict": true,