ABOUTME: React + Next.js App Router development with Server Components, TypeScript
ABOUTME: Patterns for data fetching, state management, forms, testing, and styling
React + Next.js
Quick Reference
npm run dev && npm run build && npm run test && npm run typecheckSee also: _AST_GREP.md, _PATTERNS.md, source-control
Version (determine, don't assume)
Never assume a React/Next.js/Node version from prior knowledge: it rots fast and you miss CVE fixes. Fetch the truth:
jq -r '.dependencies.react, .dependencies.next' package.json 2>/dev/null # project React + Next
cat .nvmrc 2>/dev/null # project Node
node -v # local Node
npm view react version && npm view next version # latest upstreamFor a new project, pin to the latest stable. For an existing one, read package.json and prefer idioms gated to that version or lower.
Pre-Commit Verification (MANDATORY)
Before every commit, both of these MUST pass:
make check # project-wide gate (lint, types, tests, security)
make test-e2e # end-to-end tests (or the project's e2e target)If make check is missing, scaffold it with the project-checks skill. If there is no e2e target, do NOT silently skip: flag it to the user and ask whether to proceed or add one.
Full raw toolchain (what make check should expand to):
npm run lint # ESLint
npm run typecheck # tsc --noEmit
npm run test # Vitest unit tests
npm run build # Next.js production build
npm audit --omit=dev # Dependency CVEsCore Patterns
// Server Component (default)
async function Page() {
const data = await fetchData()
return <Component data={data} />
}
// Client Component
'use client'
function Interactive() {
const [state, setState] = useState()
return <button onClick={() => setState(x => x + 1)} />
}
// Server Action
async function submit(formData: FormData) {
'use server'
await db.insert(formData)
}Project Structure
src/
├── app/ # App Router
├── components/ui/ # Primitives
├── features/*/ # Feature modules
├── lib/ # Utils
├── stores/ # Zustand
└── types/Organize by feature, not technical layer.
Server vs Client Components
Default to Server. Client only when needed.
| Server | Client |
|---|---|
| Fetch data, DB access | onClick, onChange |
| Sensitive data | useState, useEffect |
| Large deps, SEO | Browser APIs |
Key Patterns
State: TanStack Query (server state), Zustand (global client), nuqs (URL state).
Forms: Server Action + useActionState + Zod validation. useFormStatus for pending UI.
Performance: next/image with priority, dynamic() for lazy loading, React Compiler for auto-memoization.
Testing: Vitest + React Testing Library (unit), Playwright (E2E).
For detailed code examples (forms, Zustand, testing, performance), see references/react-patterns.md.
Checklist
- No
any, no unnecessary'use client' - Server/Client correctly separated
- Forms: useActionState + useFormStatus
- useOptimistic for mutations
- Images: next/image + priority
Libraries: TanStack Query, Zustand, nuqs, Zod, Vitest + Playwright