Improve NextJS application performance

To improve the performance of your app built on React and Next.js using TypeScript, you can follow several strategies.

Code Optimization

Minimize unnecessary re-renders by using React.memo, useMemo, and useCallback hooks to memoize components and functions that don’t depend on changing data. Avoid unnecessary state updates and re-renders by optimizing the usage of useState and useEffect hooks.

Using TypeScript’s type checking can catch potential errors and improve code quality.

Bundle Size Optimization

Split your code into smaller chunks using dynamic imports and code splitting. This allows you to load only the necessary code for each page or component, reducing the initial bundle size and improving load times. Analyze your bundle using tools like Webpack Bundle Analyzer to identify and eliminate any unnecessary dependencies or large libraries. Compress and optimize your assets (images, CSS, etc.) to reduce their size and improve load times. Next.js has built-in Image component that allows to compress images on the fly. It also converts then to modern image formats that are lightweight.

Server-Side Rendering (SSR) and Static Site Generation (SSG)

Utilize Next.js’s built-in features for server-side rendering and static site generation to pre-render pages and improve initial load times. This reduces the amount of work required by the client’s browser. Identify pages that don’t require real-time data and generate them statically using Next.js’s getStaticProps or getStaticPaths functions. This eliminates the need for client-side rendering and improves performance.

Performance Monitoring and Optimization

Use performance monitoring tools like Lighthouse, WebPageTest, or Chrome DevTools to identify performance bottlenecks, such as slow-loading components, large files, or long JavaScript execution times. Optimize critical rendering paths by prioritizing the loading of essential content and deferring non-critical scripts or styles. Implement lazy loading for images and other non-essential assets to load them only when they become visible in the viewport. Implement caching mechanisms for API requests or frequently accessed data to reduce server load and improve response times.

SSR Caching and Incremental Static Regeneration

Utilize Next.js’s caching capabilities to cache rendered pages on the server-side and serve them directly for subsequent requests, reducing the need for re-rendering. Implement incremental static regeneration for pages that require dynamic data. This allows you to re-generate and update specific pages at predefined intervals, ensuring the content stays fresh while reducing the load on the server.

Performance Testing and Optimization Iteration

Regularly test your app’s performance using tools like Lighthouse or Chrome DevTools to measure metrics like First Contentful Paint (FCP), Time to Interactive (TTI), and Total Blocking Time (TBT). Set performance budgets and strive to stay within them. Continuously analyze and optimize critical paths, reducing the time required for JavaScript execution, network requests, and rendering. Remember to always profile and benchmark your optimizations to ensure they have a positive impact on your app’s performance.

Improve NextJS application performance was originally published by Andrei Kaleshka at WideFix Blog on May 24, 2023.