import React from 'react';

const MyComponent = React.memo(({ name }) => {
    console.log('Rendering:', name);
    return 
{name}
;
});
        

import React, { useState, useCallback, useMemo } from 'react';

const MyComponent = () => {
    const [count, setCount] = useState(0);

    const increment = useCallback(() => setCount(c => c + 1), []);
    const doubledCount = useMemo(() => count * 2, [count]);

    return (
        

            
Count: {count}
            Increment
            
Doubled Count: {doubledCount}
        
    );
};
        

npm run build

import React, { Suspense, lazy } from 'react';

const LazyComponent = lazy(() => import('./LazyComponent'));

const MyComponent = () => (
    Loading...

The fallback prop in Suspense provides a loading indicator while the lazy-loaded component is being fetched.

6. Use React Profiler

The React Profiler is a powerful tool that helps you measure the performance of your components. By profiling your application, you can identify performance bottlenecks and understand where optimizations are needed. To use the Profiler, you can wrap your components with the Profiler component from React:

import React, { Profiler } from 'react';

const onRenderCallback = (id, phase, actualDuration) => {
    console.log(Component ${id} took ${actualDuration}ms to render during ${phase});
};

const MyComponent = () => (
    
        {/* your component code */}
    
);
        

This allows you to track the rendering times of your components and make informed decisions about where to optimize.

7. Avoid Inline Functions in Render

Defining functions inline within the render method can lead to the creation of new instances of those functions on every render. This can trigger unnecessary re-renders in child components. Instead, define your functions outside of the render method or use the useCallback hook to memoize them:

const handleClick = useCallback(() => {
    // handle click
}, []);

return Click Me;
        

8. Implement Code Splitting

Code splitting is a technique that allows you to split your code into separate bundles that can be loaded on demand. This reduces the amount of JavaScript that needs to be loaded initially, leading to faster load times. You can achieve code splitting using dynamic imports:

const loadComponent = () => import('./MyComponent');

const MyComponent = () => {
    const [Component, setComponent] = useState(null);

    const handleClick = async () => {
        const { default: LoadedComponent } = await loadComponent();
        setComponent(() => LoadedComponent);
    };

    return (
        

            Load Component
            {Component && }
        
    );
};
        

9. Optimize Images and Assets

Images can be one of the largest resources in your application. Large image files can significantly slow down loading times. Optimize images before including them in your project by compressing them using tools like ImageOptim or TinyPNG. Additionally, consider using modern image formats like WebP for better compression.

10. Monitor Performance Regularly

Regularly monitoring your app’s performance is crucial for identifying potential issues. Utilize tools like Lighthouse and WebPageTest to analyze your application's performance and receive actionable insights. Keep track of metrics like loading time, rendering time, and resource sizes to ensure optimal performance over time.

11. Use Server-Side Rendering (SSR)

Server-Side Rendering can significantly improve the performance of your React applications by rendering pages on the server rather than in the browser. This allows users to receive a fully rendered page faster, improving the perceived performance. Frameworks like Next.js make implementing SSR straightforward:

import React from 'react';

const MyPage = ({ data }) => (
    

        
{data.title}
        
{data.content}
    
);

export async function getServerSideProps() {
    const res = await fetch('https://api.example.com/data');
    const data = await res.json();

    return { props: { data } };
}

export default MyPage;
        

12. Minimize Dependencies

Every additional library or dependency you add can increase the bundle size and affect performance. Be cautious about adding new libraries, especially if they are not essential. Consider using native JavaScript or lighter alternatives to achieve the same functionality.

Conclusion

Optimizing React applications is an ongoing process that significantly enhances user experience and resource efficiency. By implementing these strategies, you can ensure your app remains fast and responsive as it scales. Remember that performance tuning is not a one-time task; it requires continuous monitoring and adjustments to adapt to changes in your app and user interactions. With careful optimization, you can create React applications that not only meet user expectations but exceed them.