Cursor rule

1---
2alwaysApply: false
3---
4 
5## Prevent Waterfall Chains in API Routes
6 
7In API routes and Server Actions, start independent operations immediately, even if you don't await them yet.
8 
9**Incorrect (config waits for auth, data waits for both):**
10 
11```typescript
12export async function GET(request: Request) {
13  const session = await auth()
14  const config = await fetchConfig()
15  const data = await fetchData(session.user.id)
16  return Response.json({ data, config })
17}
18```
19 
20**Correct (auth and config start immediately):**
21 
22```typescript
23export async function GET(request: Request) {
24  const sessionPromise = auth()
25  const configPromise = fetchConfig()
26  const session = await sessionPromise
27  const [config, data] = await Promise.all([
28    configPromise,
29    fetchData(session.user.id)
30  ])
31  return Response.json({ data, config })
32}
33```
34 
35For operations with more complex dependency chains, use `better-all` to automatically maximize parallelism (see Dependency-Based Parallelization).
36