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Next.js Patterns

For basic setup, see setup/ .

Impact Levels

CRITICAL - Breaking bugs, security holes
HIGH - Common mistakes
MEDIUM - Optimization

References

Reference Impact

references/server-vs-client.md

CRITICAL - storefront(cookies()) vs storefront()

references/token-management.md

HIGH - Cookie-based token flow in Next.js

Mental Model

The storefront() function adapts to the execution context:

Context Usage Token Storage

Client Components storefront()

Browser cookies

Server Components storefront(cookies())

Request cookies

Server Actions storefront(cookies())

Request cookies (read + write)

Root Layout storefront({ isRootLayout: true })

Memory fallback

Build time (SSG) storefront()

Memory (no user context)

Setup

Install

npm install @commercengine/storefront-sdk-nextjs

Create Config

// lib/storefront.ts export { storefront } from "@commercengine/storefront-sdk-nextjs";

Root Layout

// app/layout.tsx import { StorefrontSDKInitializer } from "@commercengine/storefront-sdk-nextjs/client"; import { storefront } from "@/lib/storefront";

// Root Layout has no request context — use isRootLayout flag const sdk = storefront({ isRootLayout: true });

export default function RootLayout({ children }: { children: React.ReactNode }) { return ( <html lang="en"> <body> <StorefrontSDKInitializer /> {children} </body> </html> ); }

Environment Variables

.env.local

NEXT_PUBLIC_STORE_ID=your-store-id NEXT_PUBLIC_API_KEY=your-api-key NEXT_BUILD_CACHE_TOKENS=true # Faster builds with token caching

Key Patterns

Server Component (Data Fetching)

// app/products/page.tsx import { storefront } from "@/lib/storefront"; import { cookies } from "next/headers";

export default async function ProductsPage() { const sdk = storefront(cookies()); const { data, error } = await sdk.catalog.listProducts({ page: 1, limit: 20, });

if (error) return <p>Error: {error.message}</p>;

return ( <div> {data.products.map((product) => ( <div key={product.id}>{product.name}</div> ))} </div> ); }

Server Actions (Mutations)

// app/actions.ts "use server";

import { storefront } from "@/lib/storefront"; import { cookies } from "next/headers"; import { redirect } from "next/navigation";

export async function loginWithEmail(email: string) { const sdk = storefront(cookies());

const { data, error } = await sdk.auth.loginWithEmail({ email, register_if_not_exists: true, });

if (error) return { error: error.message }; return { otp_token: data.otp_token, otp_action: data.otp_action }; }

export async function verifyOtp(otp: string, otpToken: string, otpAction: string) { const sdk = storefront(cookies());

const { data, error } = await sdk.auth.verifyOtp({ otp, otp_token: otpToken, otp_action: otpAction, });

if (error) return { error: error.message }; redirect("/account"); }

export async function addToCart(cartId: string, productId: string, variantId: string | null) { const sdk = storefront(cookies());

const { data, error } = await sdk.cart.addDeleteCartItem( { id: cartId }, { product_id: productId, variant_id: variantId, quantity: 1 } );

if (error) return { error: error.message }; return { cart: data.cart }; }

Static Site Generation (SSG)

// app/products/[slug]/page.tsx import { storefront } from "@/lib/storefront";

// Pre-render product pages at build time export async function generateStaticParams() { const sdk = storefront(); // No cookies at build time const { data } = await sdk.catalog.listProducts({ limit: 100 });

return (data?.products ?? []).map((product) => ({ slug: product.slug, })); }

export default async function ProductPage({ params }: { params: { slug: string } }) { const sdk = storefront(); // No cookies for static pages const { data, error } = await sdk.catalog.getProductDetail({ product_id_or_slug: params.slug, });

if (error) return <p>Product not found</p>; const product = data.product;

return ( <div> <h1>{product.name}</h1> <p>{product.selling_price}</p> {/* AddToCartButton is a Client Component */} </div> ); }

Client Component

"use client";

import { storefront } from "@/lib/storefront";

export function AddToCartButton({ productId, variantId }: Props) { async function handleClick() { const sdk = storefront(); // No cookies in client components const { data, error } = await sdk.cart.addDeleteCartItem( { id: cartId }, { product_id: productId, variant_id: variantId, quantity: 1 } ); }

return <button onClick={handleClick}>Add to Cart</button>; }

SEO Metadata

Use Next.js generateMetadata with CE product fields for meta tags, Open Graph, and structured data:

// app/products/[slug]/page.tsx import { storefront } from "@/lib/storefront"; import type { Metadata } from "next";

export async function generateMetadata({ params }: { params: { slug: string } }): Promise<Metadata> { const sdk = storefront(); // No cookies — metadata runs at build time for static pages const { data } = await sdk.catalog.getProductDetail({ product_id_or_slug: params.slug, });

const product = data?.product; if (!product) return { title: "Product Not Found" };

const image = product.images?.[0];

return { title: product.name, description: product.short_description, openGraph: { title: product.name, description: product.short_description ?? undefined, images: image ? [{ url: image.url_standard, alt: image.alternate_text ?? product.name }] : [], }, }; }

CE field → meta tag mapping:

Meta Tag CE Field

<title>

product.name

meta description

product.short_description

og:image

product.images[0].url_standard

og:image:alt

product.images[0].alternate_text

Canonical URL Build from product.slug

For category/PLP pages, use the category name and description from listCategories() . For search pages, use the search query.

Common Pitfalls

Level Issue Solution

CRITICAL Missing cookies() in Server Components Use storefront(cookies()) for user-specific data on the server

CRITICAL Auth in Server Components instead of Actions Auth endpoints that return tokens MUST be in Server Actions, not Server Components

HIGH Missing StorefrontSDKInitializer

Required in root layout for automatic anonymous auth and session continuity

HIGH Using cookies() in Client Components Client Components use storefront() (no cookies) — tokens managed via browser cookies

MEDIUM Slow builds Set NEXT_BUILD_CACHE_TOKENS=true for token caching during SSG

MEDIUM Root Layout missing isRootLayout flag Root Layout runs outside request context — use storefront({ isRootLayout: true })

ce-nextjs-patterns

Safety Notice

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.env.local

Source Transparency

Related Skills

ce-cart-checkout

ce-auth

ce-orders

ce