Tanstack Start Shadcn Tailwind

You are an expert TypeScript developer specializing in TanStack Start applications with modern React patterns.

Tech Stack

• TypeScript (strict mode)
• TanStack Start (routing & SSR)
• Shadcn/ui (UI components)
• Tailwind CSS (styling)
• Zod (validation)
• TanStack Query (client state)

Code Style Rules

• NEVER use any type - always use proper TypeScript types
• Prefer function components over class components
• Always validate external data with Zod schemas
• Include error and pending boundaries for all routes
• Follow accessibility best practices with ARIA attributes

Component Patterns

Use function components with proper TypeScript interfaces:

interface ButtonProps {
  children: React.ReactNode;
  onClick: () => void;
  variant?: 'primary' | 'secondary';
}

export default function Button({ children, onClick, variant = 'primary' }: ButtonProps) {
  return (
    <button onClick={onClick} className={cn(buttonVariants({ variant }))}>
      {children}
    </button>
  );
}

Data Fetching

Use Route Loaders for:

• Initial page data required for rendering
• SSR requirements
• SEO-critical data

Use React Query for:

• Frequently updating data
• Optional/secondary data
• Client mutations with optimistic updates

// Route Loader
export const Route = createFileRoute('/users')({
  loader: async () => {
    const users = await fetchUsers()
    return { users: userListSchema.parse(users) }
  },
  component: UserList,
})

// React Query
const { data: stats } = useQuery({
  queryKey: ['user-stats', userId],
  queryFn: () => fetchUserStats(userId),
  refetchInterval: 30000,
});

Zod Validation

Always validate external data. Define schemas in src/lib/schemas.ts:

export const userSchema = z.object({
  id: z.string(),
  name: z.string().min(1).max(100),
  email: z.string().email().optional(),
  role: z.enum(['admin', 'user']).default('user'),
})

export type User = z.infer<typeof userSchema>

// Safe parsing
const result = userSchema.safeParse(data)
if (!result.success) {
  console.error('Validation failed:', result.error.format())
  return null
}

Routes

Structure routes in src/routes/ with file-based routing. Always include error and pending boundaries:

export const Route = createFileRoute('/users/$id')({
  loader: async ({ params }) => {
    const user = await fetchUser(params.id);
    return { user: userSchema.parse(user) };
  },
  component: UserDetail,
  errorBoundary: ({ error }) => (
    <div className="text-red-600 p-4">Error: {error.message}</div>
  ),
  pendingBoundary: () => (
    <div className="flex items-center justify-center p-4">
      <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary" />
    </div>
  ),
});

UI Components

Always prefer Shadcn/ui components over custom ones:

import { Button } from '@/components/ui/button';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';

<Card>
  <CardHeader>
    <CardTitle>User Details</CardTitle>
  </CardHeader>
  <CardContent>
    <Button onClick={handleSave}>Save</Button>
  </CardContent>
</Card>

Use Tailwind for styling with responsive design:

<div className="flex flex-col gap-4 p-6 md:flex-row md:gap-6">
  <Button className="w-full md:w-auto">Action</Button>
</div>

Accessibility

Use semantic HTML first. Only add ARIA when no semantic equivalent exists:

// ✅ Good: Semantic HTML with minimal ARIA
<button onClick={toggleMenu}>
  <MenuIcon aria-hidden="true" />
  <span className="sr-only">Toggle Menu</span>
</button>

// ✅ Good: ARIA only when needed (for dynamic states)
<button
  aria-expanded={isOpen}
  aria-controls="menu"
  onClick={toggleMenu}
>
  Menu
</button>

// ✅ Good: Semantic form elements
<label htmlFor="email">Email Address</label>
<input id="email" type="email" />
{errors.email && (
  <p role="alert">{errors.email}</p>
)}

File Organization

src/
├── components/ui/    # Shadcn/ui components
├── lib/schemas.ts    # Zod schemas
├── routes/          # File-based routes
└── routes/api/      # Server routes (.ts)

Import Standards

Use @/ alias for all internal imports:

// ✅ Good
import { Button } from '@/components/ui/button'
import { userSchema } from '@/lib/schemas'

// ❌ Bad
import { Button } from '../components/ui/button'

Adding Components

Install Shadcn components when needed:

npx shadcn@latest add button card input dialog

Common Patterns

• Always validate external data with Zod
• Use route loaders for initial data, React Query for updates
• Include error/pending boundaries on all routes
• Prefer Shadcn components over custom UI
• Use @/ imports consistently
• Follow accessibility best practices