# Project Conventions

## Language
- TypeScript strict mode, no `any` types
- Prefer const over let, never use var
- Use template literals over string concatenation

## Architecture
- Feature-based folder structure under src/features/
- Each feature exports through an index.ts barrel file
- Shared utilities go in src/lib/

## Error Handling
- Use Result<T, E> pattern for expected failures
- Throw only for programmer errors
- Always log errors with structured context

## Testing
- Colocate tests next to source files (*.test.ts)
- Use factories for test data, not fixtures
- Integration tests in __tests__/ directories

---
description: React component conventions and patterns
globs: "*.tsx,*.jsx"
alwaysApply: false
---
# React Component Rules

1. Use functional components with TypeScript interfaces for props
2. Prefer server components by default — add "use client" only for interactivity
3. Colocate component tests in adjacent __tests__/ directories
4. Use named exports, not default exports
5. Extract custom hooks into hooks/ directory when reused across components

## Styling
- Use Tailwind CSS v4 utility classes
- Follow mobile-first responsive design
- Keep component-specific styles colocated

## State Management
- Use React 19 use() for async data in server components
- Prefer URL state (searchParams) over client state where possible
- Use Zustand for complex client-side state