nextjs-app-router-data-fetching
Data fetching patterns for Next.js 14+ App Router including async Server Components and Server Actions. PROACTIVELY activate for: (1) fetching data in Server Components, (2) implementing Server Actions for mutations, (3) configuring caching and revalidation. Triggers: "fetch data", "server action", "revalidate"
What this skill does
# Next.js App Router Data Fetching
## Pattern 1: Async Server Components (Recommended)
```tsx
// app/posts/page.tsx (Server Component)
export default async function PostsPage() {
// Fetch directly in Server Component
const posts = await fetch('https://api.example.com/posts', {
next: { revalidate: 60 } // Revalidate every 60 seconds
}).then(res => res.json());
return (
<div>
{posts.map(post => (
<article key={post.id}>{post.title}</article>
))}
</div>
);
}
```
**Benefits**:
- No loading spinners (rendered on server)
- No client-server waterfalls
- Can access database directly (no API layer needed)
- Automatic request deduplication
## Pattern 2: Server Actions (For Mutations)
```tsx
// app/actions/posts.ts
'use server'
import { revalidatePath } from 'next/cache';
export async function createPost(formData: FormData) {
const title = formData.get('title');
await db.post.create({ data: { title } });
revalidatePath('/posts'); // Invalidate cache
return { success: true };
}
// app/posts/new/page.tsx
import { createPost } from '@/app/actions/posts';
export default function NewPostPage() {
return (
<form action={createPost}>
<input name="title" />
<button type="submit">Create</button>
</form>
);
}
```
## Caching Strategies
```tsx
// No caching (always fresh)
fetch('...', { cache: 'no-store' })
// Cache forever (static)
fetch('...', { cache: 'force-cache' })
// Time-based revalidation (ISR)
fetch('...', { next: { revalidate: 3600 } }) // 1 hour
// On-demand revalidation (with tags)
fetch('...', { next: { tags: ['posts'] } })
// Later: revalidateTag('posts')
```
## Anti-Pattern: useEffect for Data Fetching
```tsx
// DON'T: Client-side fetching with useEffect
'use client'
function Posts() {
const [posts, setPosts] = useState([]);
useEffect(() => {
fetch('/api/posts').then(r => r.json()).then(setPosts);
}, []);
return // ... causes client-server waterfall, loading spinner needed
}
// DO: Server Component
async function Posts() {
const posts = await fetch('...').then(r => r.json());
return // ... pre-rendered, no loading state
}
```
## Parallel Data Fetching
```tsx
export default async function Page() {
// Fetch in parallel
const [user, posts, comments] = await Promise.all([
fetchUser(),
fetchPosts(),
fetchComments(),
]);
return // ...
}
```
For database integration and advanced caching, see `resources/database-patterns.md`.
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