react-start

# React Start (`@tanstack/react-start`) This is the React Start entry skill. Use the workflow below, then load only the package skill that owns the boundary you are changing. Do not read `start-core`, Router Core, and React Router manuals in full before starting. For React Server Components patterns, see [react-start/server-components](./server-components/SKILL.md). > **CRITICAL**: All code is ISOMORPHIC by default. Loaders run on BOTH server and client. Use `createServerFn` for server-only logic. > **CRITICAL**: Do not confuse `@tanstack/react-start` with Next.js or Remix. They are completely different frameworks with different APIs. > **CRITICAL**: Types are FULLY INFERRED. Never cast, never annotate inferred values. ## Full-Stack Workflow 1. Define the route and component with `createFileRoute`. 2. Put private or server-only reads and writes in `createServerFn`; call reads directly from loaders. 3. Use `useServerFn` for component mutations, then invalidate the router or query cache after the write resolves. 4. Enforce auth in every private server function or server route. Add `beforeLoad` separately for navigation UX. 5. Run the initial SSR path, client navigation, mutation plus reload, direct anonymous endpoint request, runtime response assertion, type tests, and production build. Load `start-core/server-routes` instead of `server-functions` only when a raw HTTP endpoint is required. Load `router-core/*` only for the specific routing concern involved, such as params or search validation. ## Package API Surface `@tanstack/react-start` re-exports everything from `@tanstack/start-client-core` plus: - `useServerFn` — React hook for calling server functions from components All core APIs (`createServerFn`, `createMiddleware`, `createStart`, `createIsomorphicFn`, `createServerOnlyFn`, `createClientOnlyFn`) are available from `@tanstack/react-start`. Server utilities (`getRequest`, `getRequestHeader`, `setResponseHeader`, `setResponseHeaders`, `setResponseStatus`) are imported from `@tanstack/react-start/server`. ## Full Project Setup ### 1. Install Dependencies ```bash npm i @tanstack/react-start @tanstack/react-router react react-dom npm i -D vite @vitejs/plugin-react typescript @types/react @types/react-dom ``` ### 2. package.json ```json { "type": "module", "scripts": { "dev": "vite dev", "build": "vite build", "start": "node .output/server/index.mjs" } } ``` ### 3. tsconfig.json ```json { "compilerOptions": { "jsx": "react-jsx", "moduleResolution": "Bundler", "module": "ESNext", "target": "ES2022", "skipLibCheck": true, "strictNullChecks": true } } ``` ### 4. vite.config.ts ```ts import { defineConfig } from 'vite' import { tanstackStart } from '@tanstack/react-start/plugin/vite' import viteReact from '@vitejs/plugin-react' export default defineConfig({ plugins: [ tanstackStart(), // MUST come before react() viteReact(), ], }) ``` ### 5. Router Factory (src/router.tsx) ```tsx import { createRouter } from '@tanstack/react-router' import { routeTree } from './routeTree.gen' export function getRouter() { const router = createRouter({ routeTree, scrollRestoration: true, }) return router } ``` ### 6. Root Route (src/routes/\_\_root.tsx) ```tsx import type { ReactNode } from 'react' import { Outlet, createRootRoute, HeadContent, Scripts, } from '@tanstack/react-router' export const Route = createRootRoute({ head: () => ({ meta: [ { charSet: 'utf-8' }, { name: 'viewport', content: 'width=device-width, initial-scale=1' }, { title: 'My TanStack Start App' }, ], }), component: RootComponent, }) function RootComponent() { return ( <RootDocument> <Outlet /> </RootDocument> ) } function RootDocument({ children }: Readonly<{ children: ReactNode }>) { return ( <html> <head> <HeadContent /> </head> <body> {children} <Scripts /> </body> </html> ) } ``` ### 7. Index Route (src/routes/index.tsx) ```tsx import { createFileRoute } from '@tanstack/react-router' import { createServerFn } from '@tanstack/react-start' const getGreeting = createServerFn({ method: 'GET' }).handler(async () => { return 'Hello from TanStack Start!' }) export const Route = createFileRoute('/')({ loader: () => getGreeting(), component: HomePage, }) function HomePage() { const greeting = Route.useLoaderData() return <h1>{greeting}</h1> } ``` ## useServerFn Hook Use `useServerFn` to call server functions from React components with proper integration: ```tsx import { createServerFn, useServerFn } from '@tanstack/react-start' const updatePost = createServerFn({ method: 'POST' }) .validator((data: { id: string; title: string }) => data) .handler(async ({ data }) => { await db.posts.update(data.id, { title: data.title }) return { success: true } }) function EditPostForm({ postId }: { postId: string }) { const updatePostFn = useServerFn(updatePost) const [title, setTitle] = useState('') return ( <form onSubmit={async (e) => { e.preventDefault() await updatePostFn({ data: { id: postId, title } }) }} > <input value={title} onChange={(e) => setTitle(e.target.value)} /> <button type="submit">Save</button> </form> ) } ``` ## Global Start Configuration (src/start.ts) ```tsx import { createStart, createMiddleware } from '@tanstack/react-start' const requestLogger = createMiddleware().server(async ({ next, request }) => { console.log(`${request.method} ${request.url}`) return next() }) export const startInstance = createStart(() => ({ requestMiddleware: [requestLogger], })) ``` ## React-Specific Components All routing components from `@tanstack/react-router` work in Start: - `<RouterProvider>` — not needed in Start (handled automatically) - `<Outlet>` — renders matched child route - `<Link>` — type-safe navigation - `<Navigate>` — declarative redirect - `<HeadContent>` — renders head tags (must be in `<head>`) - `<Scripts>` — renders body scripts (must be in `<body>`) - `<Await>` — renders deferred data with Suspense - `<ClientOnly>` — renders children only after hydration - `<CatchBoundary>` — error boundary ## Hooks Reference All hooks from `@tanstack/react-router` work in Start: - `useRouter()` — router instance - `useRouterState()` — subscribe to router state - `useNavigate()` — programmatic navigation - `useSearch({ from })` — validated search params - `useParams({ from })` — path params - `useLoaderData({ from })` — loader data - `useMatch({ from })` — full route match - `useRouteContext({ from })` — route context - `Route.useLoaderData()` — typed loader data (preferred in route files) - `Route.useSearch()` — typed search params (preferred in route files) ## Common Mistakes ### 1. CRITICAL: Importing from wrong package ```tsx // WRONG — this is the SPA router, NOT Start import { createServerFn } from '@tanstack/react-router' // CORRECT — server functions come from react-start import { createServerFn } from '@tanstack/react-start' // CORRECT — routing APIs come from react-router (re-exported by Start too) import { createFileRoute, Link } from '@tanstack/react-router' ``` ### 2. HIGH: Using React hooks in beforeLoad or loader ```tsx // WRONG — beforeLoad/loader are NOT React components beforeLoad: () => { const auth = useAuth() // React hook, cannot be used here } // CORRECT — pass state via router context const rootRoute = createRootRouteWithContext<{ auth: AuthState }>()({}) ``` ### 3. HIGH: Missing Scripts component Without `<Scripts />` in the root route's `<body>`, client JavaScript doesn't load and the app won't hydrate. ## Cross-References - [start-core](../../../start-client-core/skills/start-core/SKILL.md) — core Start concepts - [router-core](../../../router-core/skills/router-core/SKILL.md) — routing fundamentals - [react-router](../../../react-router/skills/react-router/SKILL.md) — React Router hooks and components