React Component Analyzer

Project Context

• Frontend: React 18 with TypeScript
• Build tool: Vite
• State management: React Query (TanStack Query)
• Routing: React Router v6
• Styling: Tailwind CSS
• Components:

  frontend/src/components/

• Pages:

  frontend/src/pages/

• Types:

  frontend/src/types/

• Services:

  frontend/src/services/

When to Use

• "Component not rendering"
• "Props not being passed"
• "State not updating"
• "useEffect not firing"
• "TypeScript error on component"
• "React Query not fetching"
• "Infinite re-renders"

Debugging Approach

1. Component Structure

• Check component file exists and exports correctly
• Verify import paths are correct
• Check for TypeScript errors in props interface

2. Props and Types

• Verify prop types match between parent and child
• Check for optional vs required props
• Look for type mismatches with API responses

3. State and Hooks

• Check useState/useReducer initial values
• Verify useEffect dependencies
• Look for missing dependencies causing stale closures
• Check useMemo/useCallback usage

4. React Query Issues

• Verify query keys are correct
• Check enabled/refetch conditions
• Look for stale time and cache settings
• Verify mutation invalidations

Common Issues

// Check: Is it exported correctly?
export default ComponentName;  // or
export { ComponentName };

// Check: Is the route configured?
<Route path="/page" element={<ComponentName />} />

// Check: Does interface match API response?
interface Project {
  id: number;
  title: string;  // API might return 'name' not 'title'
}

// Check: Dependencies array
useEffect(() => {
  // This only runs when `id` changes
}, [id]);  // Missing dependency?

// Check: Query invalidation after mutation
const mutation = useMutation({
  onSuccess: () => {
    queryClient.invalidateQueries({ queryKey: ['projects'] });
  }
});

Key Files to Check

frontend/src/
├── components/
│   ├── common/          # Shared components
│   ├── projects/        # Project-specific components
│   └── ui/              # UI primitives
├── pages/
│   ├── ExplorePage.tsx  # Explore/discovery page
│   ├── ProjectPage.tsx  # Single project view
│   └── DashboardPage.tsx
├── types/
│   ├── models.ts        # Data model types
│   └── api.ts           # API response types
├── services/
│   ├── api.ts           # Axios instance
│   └── projects.ts      # Project API calls
└── hooks/
    └── useProjects.ts   # Custom hooks

Type Checking Tips

# Run TypeScript check
cd frontend && npx tsc --noEmit

# Check specific file
npx tsc --noEmit src/components/MyComponent.tsx

Browser DevTools

• React DevTools: Inspect component tree, props, state
• Network tab: Verify API requests/responses
• Console: Check for React warnings/errors