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260223:1415 20260223 nextJS & nestJS Best pratices
2026-02-23 14:15:06 +07:00

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# Route Handlers
Create API endpoints with `route.ts` files.
## Basic Usage
```tsx
// app/api/users/route.ts
export async function GET() {
const users = await getUsers()
return Response.json(users)
}
export async function POST(request: Request) {
const body = await request.json()
const user = await createUser(body)
return Response.json(user, { status: 201 })
}
```
## Supported Methods
`GET`, `POST`, `PUT`, `PATCH`, `DELETE`, `HEAD`, `OPTIONS`
## GET Handler Conflicts with page.tsx
**A `route.ts` and `page.tsx` cannot coexist in the same folder.**
```
app/
├── api/
│ └── users/
│ └── route.ts # /api/users
└── users/
├── page.tsx # /users (page)
└── route.ts # Warning: Conflicts with page.tsx!
```
If you need both a page and an API at the same path, use different paths:
```
app/
├── users/
│ └── page.tsx # /users (page)
└── api/
└── users/
└── route.ts # /api/users (API)
```
## Environment Behavior
Route handlers run in a **Server Component-like environment**:
- Yes: Can use `async/await`
- Yes: Can access `cookies()`, `headers()`
- Yes: Can use Node.js APIs
- No: Cannot use React hooks
- No: Cannot use React DOM APIs
- No: Cannot use browser APIs
```tsx
// Bad: This won't work - no React DOM in route handlers
import { renderToString } from 'react-dom/server'
export async function GET() {
const html = renderToString(<Component />) // Error!
return new Response(html)
}
```
## Dynamic Route Handlers
```tsx
// app/api/users/[id]/route.ts
export async function GET(
request: Request,
{ params }: { params: Promise<{ id: string }> }
) {
const { id } = await params
const user = await getUser(id)
if (!user) {
return Response.json({ error: 'Not found' }, { status: 404 })
}
return Response.json(user)
}
```
## Request Helpers
```tsx
export async function GET(request: Request) {
// URL and search params
const { searchParams } = new URL(request.url)
const query = searchParams.get('q')
// Headers
const authHeader = request.headers.get('authorization')
// Cookies (Next.js helper)
const cookieStore = await cookies()
const token = cookieStore.get('token')
return Response.json({ query, token })
}
```
## Response Helpers
```tsx
// JSON response
return Response.json({ data })
// With status
return Response.json({ error: 'Not found' }, { status: 404 })
// With headers
return Response.json(data, {
headers: {
'Cache-Control': 'max-age=3600',
},
})
// Redirect
return Response.redirect(new URL('/login', request.url))
// Stream
return new Response(stream, {
headers: { 'Content-Type': 'text/event-stream' },
})
```
## When to Use Route Handlers vs Server Actions
| Use Case | Route Handlers | Server Actions |
|----------|----------------|----------------|
| Form submissions | No | Yes |
| Data mutations from UI | No | Yes |
| Third-party webhooks | Yes | No |
| External API consumption | Yes | No |
| Public REST API | Yes | No |
| File uploads | Both work | Both work |
**Prefer Server Actions** for mutations triggered from your UI.
**Use Route Handlers** for external integrations and public APIs.