New Feature Nextjs

new-feature-nextjs

Do not open any file for editing until all 6 steps are completed.

---

Step 1 — Define the feature surface

Write the surface in plain text before any code:

Feature name: users
Routes: /users (list), /users/[id] (detail)
Mutations: createUser, updateUser, deleteUser
Reads: getUser(id), listUsers()
Cache tags: user(id), userList(), userOrders(userId)

If you can't fill all 5 lines in 2 sentences each, the scope is unclear — clarify with the user first.

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Step 2 — Pick the folder location (Principle C1)

| Scope | Location | |-------|----------| | Reusable everywhere (Button, Input) | src/components/ui/ | | Belongs to one business domain | src/features// | | Pure helper used in 2+ features | src/lib// | | Used in exactly one place | colocate next to that place (Principle C6) |

For a new feature, default to src/features// with this structure:

src/features//
├── components/         # JSX (server + client)
├── actions.ts          # Server Actions
├── repository.ts       # Drizzle adapter (only file importing drizzle-orm)
├── protocols.ts        # Repository protocol/interface
├── schema.ts           # Zod schemas
└── store.ts            # Zustand (only if genuinely needed)

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Step 3 — Add cache tags FIRST (Principle D1)

Before writing any Server Action, add the tags to src/lib/cache/tags.ts:

// src/lib/cache/tags.ts
export const tags = {
  // ... existing tags
  user: (id: string) => `user:${id}` as const,
  userList: () => 'user:list' as const,
} as const;

Rule: zero revalidateTag('magic-string') in the new feature. Every invalidation goes through the typed DSL. Typos must be compile errors.

---

Step 4 — Build bottom-up (parallel to FastAPI new-feature skill)

1. Schema (Zod)         → src/features//schema.ts
2. Repository protocol  → src/features//protocols.ts
3. Repository impl      → src/features//repository.ts (Drizzle)
4. Server Actions       → src/features//actions.ts (uses tags + repo via Protocol)
5. Components (server)  → src/features//components/Page.tsx
6. Components (client)  → src/features//components/.tsx ('use client')
7. Route               → src/app//page.tsx (thin, /page.tsx` stays under 20 lines and just imports `Page` (Principle C2)

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## Step 5 — Wire Suspense + PPR (Principles D3, D4)

Streaming setup in the page:

```tsx
// src/app/users/page.tsx
import { UsersPage } from '@/features/users/components/UsersPage';
import { usersRepo } from '@/features/users/repository';

export const experimental_ppr = true;  // D4

export default function Page() {
  const usersPromise = usersRepo.list(50);  // not awaited
  return ;  // streamed via Suspense
}

Server feature page wraps async children in ``:

// src/features/users/components/UsersPage.tsx
import { Suspense } from 'react';
import { UserList } from './UserList';

export function UsersPage({ usersPromise }: Props) {
  return (
    }>
      
    
  );
}

Client leaf unwraps with use():

'use client';
import { use } from 'react';

export function UserList({ usersPromise }: Props) {
  const users = use(usersPromise);
  return ...;
}

---

Step 6 — Verify principles before committing

Run these grep checks:

# C2: page is thin (/page.tsx

# C3: file size cap
find src/features/ -name "*.ts*" | xargs wc -l | sort -rn | head

# C4: no 'use client' on pages or layouts
grep -rn "'use client'" src/app/ | grep -E "(page|layout)\.tsx"

# C5: errors are values, not throws (in Server Actions)
grep -n "throw new" src/features//actions.ts

# C8: no `any` and no @ts-ignore
grep -rn ": any\b\| as any\b\|@ts-ignore" src/features//

# C10: no inline styles
grep -rn "style=\{\{" src/features//

# D1: every revalidateTag goes through tags.X()
grep -n "revalidateTag(['\"]" src/features//  # must be empty

# D6: drizzle-orm imported only from repository.ts
grep -rn "from 'drizzle-orm" src/features//  # only repository.ts allowed

| Check | Expected result | |-------|----------------| | page.tsx line count | 200 LOC | refactor before commit | | 'use client' on page/layout | zero hits | | throw new in actions.ts | zero hits (return errors as values) | | any / @ts-ignore | zero hits | | style={{}} | zero hits | | revalidateTag('...') magic string | zero hits | | drizzle-orm outside repository.ts | zero hits |

pnpm typecheck
pnpm lint

Both must pass.

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Verification checklist

• [ ] Surface defined in writing before any code
• [ ] Folder location follows feature-driven colocation
• [ ] Cache tags added to lib/cache/tags.ts before Server Actions
• [ ] Build order followed: schema → protocol → repo → action → component → route
• [ ] Server fetch passes Promise down; client unwraps with use()
• [ ] PPR enabled if route has static + dynamic mix
• [ ] All 8 grep checks pass
• [ ] pnpm typecheck && pnpm lint exits 0

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: yerdaulet-damir
• Source: yerdaulet-damir/vibe-coding-rules
• License: MIT
• Homepage: https://vibecodex-omega.vercel.app

Install and usage instructions live in the source repository linked above.