Ways to Optimize Applications

Gzip Compression

Data compression using Gzip allows reducing data volume transmitted from server to client. This is especially important for reducing page load times. In most cases Gzip compression is enabled by default on server, but it's recommended to check its work on all static resources (HTML, CSS, JS).

Using CDN (Content Delivery Network)

CDN is network of distributed servers that speeds up delivery of static content (images, CSS, JavaScript) to user by choosing closest server. This reduces response time and speeds up page loading.

• Example: Using services such as Amazon S3 or Cloudflare for storing and delivering images, styles and scripts.

Static Resource Caching

To speed up application work it's important to cache static files (images, fonts, CSS and JavaScript files). This reduces number of server requests and speeds up site loading. Use Cache-Control, ETag and Last-Modified headers to configure proper caching.

Code Splitting

Code splitting using Webpack or other tools allows loading only needed code parts, not entire application at once. This reduces initial page load time.

• Example: Using React.lazy and Suspense for dynamic component loading only when needed.

Using HTTP/2 Instead of HTTP/1

HTTP/2 significantly speeds up data transfer, allowing parallel resource loading and header compression. It also reduces delays by optimizing network request handling. Using HTTP/2 is one of simple ways to improve performance.

Lazy Loading

Lazy loading is technique where resources or components are loaded only when they become necessary. This reduces initial page load, improving its load time.

• Example: Loading images only as they appear in visible screen area using loading="lazy" in <img> tags.

Optimizing Re-renders with useMemo, useCallback and memo

Frequent renders can significantly slow down application work. To reduce their number, you can use hooks useMemo, useCallback and React.memo:

• useMemo: Caches computation result if dependencies don't change.
• useCallback: Caches function so it's not recreated on each render.
• React.memo: Component memoization preventing its re-render if props haven't changed.

Using Web Workers

Web Workers allow executing resource-intensive operations in separate threads without blocking application's main thread. This is useful for data processing or performing complex calculations in background.

• Example: Using Web Workers for processing large data volumes on client without blocking UI.

Virtualization and Pagination

To optimize performance when working with large lists or data tables you can use virtualization or pagination:

• Virtualization: Only list elements visible on screen are displayed, reducing rendering load.
• Pagination: Breaking large data into pages, reducing number of elements that need to be rendered.

Image Optimization

• Using CDN for storing and fast image delivery.
• Lazy loading images to load them only as needed.
• Using progressive images (e.g., WebP or JPEG 2000 formats) that load with low quality, then improve to higher quality.

Using debounce/throttle for Input

To prevent frequent requests during data input you can use debounce or throttle. This allows reducing number of requests sent to server, e.g., when filtering data or searching.

• Debounce: Waits certain time after last input before executing function (e.g., for search as you type).
• Throttle: Executes function at fixed intervals (e.g., limiting number of server requests).

Performance Measurement Methods and Metrics

For effective optimization it's important to track your application's performance. Here are several tools that will help you measure various metrics:

1. Performance in DevTools: Performance tab in browser developer tools allows recording all page actions, including rendering, JavaScript execution and requests.

2. Lighthouse: Built-in Chrome utility for measuring page performance, SEO, accessibility and other metrics.

3. Web-vitals: Set of metrics for measuring performance such as Largest Contentful Paint (LCP), First Input Delay (FID) and Cumulative Layout Shift (CLS).

4. React Profiler: React extension that helps track unnecessary re-renders and identify performance bottlenecks.

5. WebPageTest: Site for analyzing web page performance with ability to test load speed from different regions and on different devices.