The web development landscape continues to evolve rapidly. Here are the best practices I follow when building modern web applications. ## Performance First Performance isn't just about speed—it's about user experience and business results. ### Core Web Vitals Focus on Google's Core Web Vitals: 1. **Largest Contentful Paint (LCP)**: < 2.5s 2. **First Input Delay (FID)**: < 100ms 3. **Cumulative Layout Shift (CLS)**: < 0.1 ### Optimization Techniques ```javascript // Image optimization with Next.js import Image from 'next/image' export default function Hero() { return (

) } ``` ## Accessibility is Non-Negotiable Building accessible websites isn't just the right thing to do—it's a legal requirement in many jurisdictions. ### Key Principles - **Semantic HTML**: Use proper heading hierarchy, landmarks, and elements - **Keyboard Navigation**: Ensure all functionality is keyboard accessible - **ARIA Labels**: Provide context for screen readers - **Color Contrast**: Maintain WCAG AA standards (4.5:1 for normal text) ### Example ```jsx ``` ## Component Architecture Build components that are reusable, testable, and maintainable. ### Single Responsibility Each component should do one thing well: ```typescript // Bad: Component doing too much function UserDashboard() { // Handles auth, data fetching, UI rendering, analytics... } // Good: Separated concerns function UserDashboard() { return ( ) } ``` ## Type Safety with TypeScript TypeScript catches bugs before they reach production: ```typescript interface UserProfile { id: string; name: string; email: string; role: 'admin' | 'user' | 'guest'; } function updateProfile(userId: string, updates: Partial) { // Type-safe updates } ``` ## State Management Keep state management simple and predictable: - **Local state**: Use `useState` for component-specific state - **Shared state**: Use React Context for widely-shared data - **Server state**: Use libraries like React Query for API data - **Complex state**: Consider Zustand or Redux only when truly needed ## Testing Strategy Write tests that give you confidence: 1. **Unit tests**: For utility functions and hooks 2. **Integration tests**: For component interactions 3. **E2E tests**: For critical user flows ```typescript // Example: Testing a form component test('submits form with valid data', async () => { render() await userEvent.type(screen.getByLabelText(/name/i), 'John Doe') await userEvent.type(screen.getByLabelText(/email/i), 'john@example.com') await userEvent.click(screen.getByRole('button', { name: /submit/i })) expect(await screen.findByText(/success/i)).toBeInTheDocument() }) ``` ## Security Best Practices - **Sanitize user input**: Never trust client data - **Use HTTPS**: Always, no exceptions - **Implement CSP**: Content Security Policy headers - **Dependency audits**: Run `npm audit` regularly - **Environment variables**: Never commit secrets ## Progressive Enhancement Build experiences that work for everyone: 1. Start with working HTML 2. Enhance with CSS 3. Add JavaScript for interactivity 4. Ensure core functionality without JS ## Monitoring and Analytics You can't improve what you don't measure: - **Error tracking**: Sentry, LogRocket - **Performance monitoring**: Web Vitals, Lighthouse CI - **User analytics**: Privacy-focused tools like Plausible - **A/B testing**: For data-driven decisions ## Conclusion Modern web development requires balancing performance, accessibility, developer experience, and user needs. By following these best practices, you'll build applications that are fast, maintainable, and delightful to use. Remember: best practices evolve. Stay curious, keep learning, and always prioritize your users.