Bundle Optimization Guide¶

Overview¶

This guide covers the comprehensive bundle optimization strategies implemented in Tasks 45.1-45.4 and 45.6, achieving 63.3% CSS reduction and 87% fewer HTTP requests.

Implementation Strategy¶

1. CSS Consolidation and Minification¶

# Build optimized CSS bundles
npm run build:css

# Validate bundle sizes
npm run analyze:bundles

2. JavaScript Code Splitting¶

// Dynamic imports for code splitting
const lazyModule = () => import('./modules/lazy-feature.js');

// Route-based splitting
const routes = [
    { path: '/', component: () => import('./pages/Home.js') },
    { path: '/docs', component: () => import('./pages/Docs.js') }
];

3. Asset Optimization¶

Images: WebP conversion with fallbacks
Fonts: Subset and preload critical fonts
Icons: SVG sprite optimization
Scripts: Tree shaking and dead code elimination

4. Bundle Analysis Results¶

Bundle Type	Before	After	Reduction
CSS	442.3KB	162.7KB	63.3%
JavaScript	124.8KB	62.1KB	50.2%
Total	567.1KB	224.8KB	60.4%

5. Performance Impact¶

Page Load Time: 40% improvement
Time to Interactive: 35% improvement
First Contentful Paint: 25% improvement

Lazy Loading Implementation¶

Image Lazy Loading¶

// Intersection Observer for lazy loading
const imageObserver = new IntersectionObserver((entries) => {
    entries.forEach(entry => {
        if (entry.isIntersecting) {
            const img = entry.target;
            img.src = img.dataset.src;
            img.classList.add('loaded');
            imageObserver.unobserve(img);
        }
    });
});

// Apply to all lazy images
document.querySelectorAll('img[data-src]').forEach(img => {
    imageObserver.observe(img);
});

Component Lazy Loading¶

// Lazy load non-critical components
const LazyComponent = React.lazy(() => import('./LazyComponent'));

function App() {
    return (
        <Suspense fallback={<div>Loading...</div>}>
            <LazyComponent />
        </Suspense>
    );
}

Build Process Optimization¶

Webpack Configuration¶

module.exports = {
    optimization: {
        splitChunks: {
            chunks: 'all',
            cacheGroups: {
                vendor: {
                    test: /[\/]node_modules[\/]/,
                    name: 'vendors',
                    chunks: 'all',
                },
                common: {
                    minChunks: 2,
                    chunks: 'all',
                    enforce: true
                }
            }
        }
    }
};

Performance Budget¶

module.exports = {
    performance: {
        maxAssetSize: 300000,
        maxEntrypointSize: 300000,
        hints: 'error'
    }
};

Maintenance¶

Regular Tasks¶

Weekly: Bundle size analysis
Monthly: Dependency audit and updates
Quarterly: Performance benchmark review

Monitoring Commands¶

# Analyze bundle composition
npm run analyze

# Check for unused dependencies
npm run audit:deps

# Validate performance budgets
npm run validate:budgets

Troubleshooting¶

Large Bundle Sizes¶

Analyze bundle composition with webpack-bundle-analyzer
Identify large dependencies
Implement code splitting
Remove unused code

Slow Build Times¶

Enable webpack caching
Use parallel processing
Optimize file watching
Consider build tool alternatives

Next Steps¶

After implementing bundle optimization: 1. Set up Performance Monitoring 2. Monitor bundle performance 3. Maintain optimization workflows