sharenet/frontend/PERFORMANCE_GUIDE.md

Frontend Performance Optimization Guide

Quick Performance Solutions

1. For Immediate Speed Improvement (Recommended)

Build and run the production version:

npm run performance

This builds the optimized production version and runs it on port 3001, which will be significantly faster than the development server.

2. For Development Speed

Use the fast development mode:

npm run dev:fast

This runs the development server with optimized settings on port 3001.

Port Configuration

• Backend API: Port 3000 (default)
• Frontend Development: Port 3000 (default) or 3001 (fast mode)
• Frontend Production: Port 3001

Performance Strategies

Development vs Production Performance

Mode	Speed	Port	Features	Use Case
npm run dev	Slow	3000	Hot reload, debugging	Development
npm run dev:fast	Medium	3001	Hot reload, optimized	Development
npm run performance	Fast	3001	Optimized, no hot reload	Testing/Production

Why Development Mode is Slower

Development mode includes:

• Hot module replacement (HMR)
• Source maps
• Unminified code
• Development warnings
• Type checking
• ESLint checking

Production Mode Benefits

Production mode provides:

• Minified and optimized code
• Tree shaking
• Code splitting
• Optimized images
• Faster rendering
• Smaller bundle sizes

Performance Optimization Techniques

1. Code Splitting

The Next.js config now includes automatic code splitting:

• Vendor chunks are separated
• Dynamic imports for large components
• Route-based splitting

2. Bundle Optimization

• SWC Minification: Faster than Terser
• Package Optimization: Optimized imports for UI libraries
• Tree Shaking: Removes unused code

3. Image Optimization

• WebP/AVIF formats: Smaller file sizes
• Responsive images: Automatic sizing
• Lazy loading: Images load when needed

4. Caching Strategies

• Static generation: Pre-built pages
• Incremental Static Regeneration: Fresh content with caching
• CDN optimization: Distributed content delivery

Performance Monitoring

Analyze Bundle Size

npm run build:analyze

This will show you:

• Bundle size breakdown
• Largest dependencies
• Optimization opportunities

Type Checking

npm run type-check

Ensures TypeScript types are correct without running the full dev server.

Advanced Optimizations

1. Component-Level Optimizations

// Use React.memo for expensive components
const ExpensiveComponent = React.memo(({ data }) => {
  return <div>{/* expensive rendering */}</div>
});

// Use useMemo for expensive calculations
const expensiveValue = useMemo(() => {
  return expensiveCalculation(data);
}, [data]);

// Use useCallback for event handlers
const handleClick = useCallback(() => {
  // handle click
}, []);

2. Lazy Loading

// Lazy load components
const LazyComponent = dynamic(() => import('./LazyComponent'), {
  loading: () => <div>Loading...</div>
});

3. Virtual Scrolling

For large lists, consider virtual scrolling libraries:

• react-window
• react-virtualized

Environment-Specific Optimizations

Development Environment

1. Use Turbopack: Already enabled in your config
2. Disable unnecessary features: Remove console logs in production
3. Optimize imports: Use the optimizePackageImports config

Production Environment

1. Enable compression: Gzip/Brotli compression
2. Use CDN: Serve static assets from CDN
3. Enable caching: Browser and server-side caching
4. Monitor performance: Use tools like Lighthouse

Troubleshooting Slow Performance

Common Issues

1. Large bundle size: Use bundle analyzer
2. Unnecessary re-renders: Use React DevTools Profiler
3. Slow API calls: Implement caching and loading states
4. Heavy third-party libraries: Consider alternatives or lazy loading

Performance Checklist

• Use production build for testing
• Implement code splitting
• Optimize images
• Minimize bundle size
• Use React.memo where appropriate
• Implement proper caching
• Monitor Core Web Vitals

Recommended Workflow

1. Development: Use npm run dev:fast for faster development
2. Testing: Use npm run performance to test production-like performance
3. Production: Use npm run build && npm run start for deployment

Performance Metrics to Monitor

• First Contentful Paint (FCP): < 1.8s
• Largest Contentful Paint (LCP): < 2.5s
• First Input Delay (FID): < 100ms
• Cumulative Layout Shift (CLS): < 0.1

Tools for Performance Analysis

• Lighthouse: Built into Chrome DevTools
• WebPageTest: Detailed performance analysis
• React DevTools Profiler: Component-level performance
• Bundle Analyzer: Bundle size analysis