How to improve React Native performance?

React Native is a popular framework for making apps that work on different devices. It’s liked, because it’s flexible and quick to use, making apps that feel almost like they’re native to each device.

But, it has some problems with how fast it works. For example, it doesn’t handle animations very well, and it can’t do multiple tasks at the same time. When apps need to do a lot of complex things, it can slow them down.

People in the community are trying hard to make React Native better. They’re fixing issues and adding new features. But sometimes, adding too many new things can make apps slow down even more.

So, before we talk about how to make React Native apps faster, it’s important to know why they can be slow in the first place.

Reasons for a Slow React Native App

A React Native app may be underperforming for several reasons. The following are some typical reasons why React Native apps operate slowly:

• Complex UI: Apps with intricate UI designs, involving numerous nested components, take longer to render, leading to performance issues.
• Complex Animations: Poorly implemented or overly intricate animations can significantly slow down component rendering.
• Unnecessary Re-renders: Overusing setState or neglecting shouldComponentUpdate lifecycle method can cause unnecessary re-renders. This results in performance overhead due to components re-rendering needlessly or performing resource-intensive calculations on every render.
• Optimization Shortcomings: Inadequate optimization practices, such as using inappropriate components or overlooking performance optimization techniques like memoization, can hamper app speed.
• Complex Calculations: Performing intricate calculations within components can delay rendering and impact overall performance.
• Data Fetching Impact: Fetching excessive data for a specific component or page increases loading times and undermines performance.

Recognizing these underlying causes of slow performance is the initial step towards finding effective solutions. Now let’s look at how you can improve the app’s performance.

Ways to Improve the React Native App Performance

1. Network Optimization

App performance can be influenced by network operations. To improve it, follow these steps:

• Reduce HTTP requests by consolidating API calls or adopting more efficient data retrieval approaches.
• Introduce caching systems to cut down on network round-trips, especially for static or less frequently updated data.
• Utilize resources such as react-native-offline or react-native-fast-image to enable offline caching and optimize image loading for improved efficiency.

2. Optimize Launch Speed

The app’s speed is gauged by how fast it is launched. For this purpose, you might need to ensure proper rendering, reduce the app’s memory usage, and reduce the bundle size. Leverage React Native features like Hermes integration and Memoization to achieve these improvements.

3. Improve Debugging Speed

Productivity and app speed is hampered excessively by the debugging rate. You will notice that the number of bugs in an app can lower agility. If you want to speed up the process and ensure the removal of all the bugs, you should use Flipper. It works well with React Native and native app systems.

The layout comprises of network inspector and contains a detailed log. By integrating it with your code, you can monitor the functions, logic, and methods to reduce your debugging time.

4. Cache the Image Files

Caching is a great way to solve issues associated with loading and rerendering images from remote endpoints. Image caching essentially means downloading an image to the local storage in the app’s cache directory (or any other directory that is accessible to the app) and loading it from local storage next time the image loads. But caching with the image component is supported in iOS alone, not in Android.

Here’s how you would cache an image:

<Image
  source={{
    uri: 'https://unsplash.it/200/200?image=8'
    cache: 'only-if-cached'
  }}
  style={{ ... }}
/>        

If you’re working with a basic React Native app, consider using React Native FastImage — a convenient solution that automatically handles image caching without the need for additional code. FastImage, being part of the react-native-fast-image library, empowers us to seamlessly integrate image caching functionality, significantly enhancing the overall performance of image loading.

import FastImage from 'react-native-fast-image'

const App = () => (
  <FastImage
        style={{ ... }}
        source={{
            uri: 'https://unsplash.it/200/200?image=8',
            priority: FastImage.priority.normal,
            cache: FastImage.cacheControl.cacheOnly
        }}
    />
)        

5. Optimize Images

While caching will help with re-rendering, you may want to ensure that images don’t delay your app launch. As a result, it is essential to optimize your images to improve app performance.

Optimizing images is crucial for enhancing app performance, especially when avoiding image-related delays during the app launch despite caching efforts.

• For small pictures like icons, pick SVG
• For bigger, more detailed images like product photos, go with PNG
• Employ lazy-loading techniques for images to defer their loading until necessary, minimizing unnecessary network requests and contributing to quicker initial app load times.
• Resolution shouldn’t be too high.
• WEBP format can help reduce the image size for both iOS and Android platforms.

6. Optimize Rendering

Enhancing rendering efficiency is vital for optimizing performance in your React Native application:

• Use the VirtualizedList component for efficient rendering of large lists.
• Employ component or React.memo to minimize unnecessary re-rendering of components.
• Opt for the Animated API over inline styles to ensure smoother animations.

7. Memory Management

Effective memory management plays a pivotal role in app performance. Adhere to these practices:

• Prevent memory leaks by unsubscribing from event listeners, clearing intervals, or eliminating object references when they’re no longer required.
• Limit the usage of the React Native bridge and minimize unnecessary data conversions between JavaScript and native code.
• Employ efficient data structures and algorithms to decrease memory usage and enhance overall performance.

8. Remove unnecessary libraries and features

Every inclusion of a library in a React or React Native app adds to its overall size and impact. Therefore, it’s crucial to selectively incorporate only the necessary libraries and functionalities while eliminating unnecessary dependencies.

Features like animations, navigations, tabs, and similar elements can notably affect screen load times, especially when extensively used, leading to performance degradation.

9. Optimize React Native Code

Efficient rendering is crucial to manage both time and memory resources effectively during application execution. Optimizing code is a common practice to ensure the delivery of high-performance applications. Using PureComponent for text elements prevents unnecessary overrides and potential performance impacts.

Define the functions and code accurately, and introduce the most suitable code for this scenario.

10. Profile Your App

Profiling your React Native app is crucial for pinpointing and improving performance issues. Use tools like React Native Performance, Flipper, or Chrome DevTools to analyze CPU usage, rendering speed, and memory consumption. Focus on optimizing functions/components with high execution times, addressing slow rendering through component optimization, and identifying and fixing memory leaks. This targeted approach enhances your app’s responsiveness and overall user experience.

So, why Performance Optimization Is Important?

• Improved Data Processing Speed: Performance optimization techniques help organizations process and analyze data faster, enabling real-time or near-real-time decision-making.
• Enhanced User Experience: Faster query response times and reduced latency improve the overall user experience, allowing for more interactive and responsive data exploration.
• Scalability: By optimizing data workflows, performance optimization allows organizations to scale their data lakehouse environments to handle ever-increasing data volumes

Conclusion

To ensure a smooth user experience, optimizing your React Native app for performance is crucial. Employ the outlined strategies to refine rendering, minimize app size, adeptly handle memory, optimize code, and streamline network operations. Consistently profiling your app helps pinpoint fresh performance issues, allowing continuous refinement. A finely tuned React Native app ensures swift, responsive, and enjoyable mobile experiences for your users.