Performance & Optimization Interview Questions

Svelte achieves performance through compile-time optimization. Generates vanilla JavaScript with minimal runtime overhead. Uses surgical DOM updates. Eliminates virtual DOM overhead.

Code splitting automatically breaks application into smaller chunks. Routes loaded on demand. Reduces initial bundle size. Uses dynamic imports. Improves load time.

Svelte compiles reactive statements into efficient JavaScript. Updates only affected DOM elements. No diffing required. Uses fine-grained reactivity system. Minimizes overhead.

Asset optimization includes minification, bundling, compression. Uses Vite for build process. Optimizes images and styles. Supports cache headers. Improves load performance.

Component optimization includes proper key usage, avoiding unnecessary updates, using tick() function. Implement efficient loops. Minimize state changes. Use proper event handling.

Lazy loading defers loading of components until needed. Uses dynamic imports. Supports route-level code splitting. Improves initial load time. Reduces bundle size.

Memory leak prevention includes proper cleanup in onDestroy, unsubscribing from stores, removing event listeners. Clear intervals/timeouts. Handle component disposal.

Prefetching loads route data before navigation. Uses sveltekit:prefetch directive. Improves perceived performance. Supports hover-based prefetching. Reduces loading time.

Store optimization includes batching updates, using derived stores efficiently, implementing selective updates. Minimize store subscribers. Handle update frequency.

Tree-shaking removes unused code during build. Reduces bundle size. Supported by default. Works with ES modules. Eliminates dead code.

Caching strategies include browser cache, service workers, SSR cache. Handle cache invalidation. Support offline functionality. Implement cache policies.

Animation optimization includes using CSS animations when possible, hardware acceleration, efficient transitions. Handle animation timing. Minimize reflows.

Large list optimization includes virtual scrolling, pagination, infinite scroll. Use keyed each blocks. Implement list chunking. Handle DOM recycling.

Image optimization includes lazy loading, responsive images, proper formats. Use srcset attribute. Implement placeholder images. Handle image compression.

Performance monitoring tracks metrics like load time, FCP, TTI. Use browser DevTools. Implement analytics. Handle performance reporting.

SSR optimization includes caching, streaming, efficient data loading. Handle server resources. Implement response compression. Optimize render time.

Resource prioritization includes critical CSS, script loading strategies, preload/prefetch. Handle resource order. Implement loading priorities.

Build optimization includes proper Vite/Rollup config, production settings, environment optimization. Handle build process. Implement build strategies.

Performance testing measures load time, interaction time, resource usage. Implement benchmarks. Handle performance metrics. Support performance monitoring.

Advanced strategies include worker threads, memory pooling, render optimization. Handle complex scenarios. Support optimization patterns.

Bundle analysis examines build output size, dependencies, chunks. Use bundle analyzers. Handle size optimization. Implement analysis tools.

Network optimization includes request batching, protocol optimization, CDN usage. Handle network caching. Implement request strategies.

Runtime optimization includes memory management, event delegation, efficient algorithms. Handle runtime performance. Implement optimization techniques.

Rendering optimization includes layout thrashing prevention, paint optimization, composite layers. Handle render performance. Implement render strategies.

State optimization includes efficient updates, state normalization, update batching. Handle state management. Implement state strategies.

Resource optimization includes asset management, resource loading, dependency optimization. Handle resource usage. Implement optimization policies.

Security optimization includes CSP, secure headers, vulnerability prevention. Handle security measures. Implement security strategies.

Monitoring tools track performance metrics, resource usage, errors. Handle monitoring systems. Implement tracking strategies.

Optimization documentation describes performance strategies. Generate performance reports. Support optimization guidelines. Implement documentation updates.