React Native Optimization Hacks by ProCoders: Boost Performance in Several Steps

React Native is a popular framework that allows developers to build mobile apps for both iOS and Android using JavaScript and React. 

The best part? You can write one codebase and have it work across platforms, making it a huge time-saver. Many companies, including some we’ve worked with here at ProCoders, choose React Native because it offers a native-like experience without the need to develop separate apps for different platforms.

While React Native is great for efficiency, like any technology, it needs to be optimized for the best performance. If not, apps can feel slow, consume too much memory, or drain a device’s battery faster than users would like. 

That’s where optimization becomes critical—it’s the difference between a smooth, responsive app and one that frustrates users. At ProCoders, we’ve helped numerous clients fine-tune their React Native apps, and in this article, we’re going to share some of the key optimization hacks we’ve learned along the way.

React Native General Performance Optimization

Avoid Inline Functions

Inline functions in JSX might seem convenient, but they can cause performance issues by triggering unnecessary re-renders. Every time a component re-renders, the inline function is re-created, which React interprets as a change, leading to more render cycles than necessary.

ProCoders Hack: To avoid this, you can use the useCallback() hook for functional components or bind functions in the constructor for class components. This ensures functions are only re-created when absolutely necessary, optimizing the render process and boosting performance.

Optimize Render Cycles

Unnecessary re-renders are one of the biggest culprits of performance lags in React Native apps. Using React.memo for functional components or shouldComponentUpdate for class components can help control when a component re-renders by checking if its props have changed.

ProCoders Hack: For components that rely on complex data structures, you can implement custom comparison logic for deep comparisons. This gives you finer control over when re-renders should happen, helping avoid performance hits.

React Native Image Optimization Tips

Lazy Loading Images

Loading all images at once can increase memory usage and slow down your app’s performance. Instead, you should lazy load images—only loading them when they are visible on the screen. This helps reduce memory consumption and speeds up the initial load time.

ProCoders Hack: The react-native-fast-image library is a great tool for this, offering efficient caching and loading mechanisms that further improve performance when dealing with images.

Use Proper Image Formats

Choosing the right image format can make a significant difference in loading times. For example, using WebP images, which are smaller in size without losing quality, can reduce load times and save memory.

ProCoders Hack: To make sure your images are optimized, use libraries like react-native-image-resizer to resize and compress images, reducing their size without sacrificing clarity or performance.

React Native Optimization Hacks: Managing Large Lists

FlatList Optimization

When dealing with large datasets, rendering everything at once can cause significant performance bottlenecks. Instead of using ScrollView, which renders all items at once, opt for FlatList, which lazily renders items as needed, improving both memory usage and performance.

ProCoders Hack: To further boost performance, enable removeClippedSubviews, initialNumToRender, and maxToRenderPerBatch in FlatList. These options allow you to control how many items are rendered initially and how efficiently off-screen items are handled, reducing memory consumption.

Virtualization of Lists

For very large lists, virtualization is key to managing performance. FlatList and SectionList offer props like windowSize and getItemLayout that give you better control over how lists are rendered, ensuring that only the items currently in view are rendered, while others are kept in memory efficiently.

ProCoders Hack: When rendering long lists, it’s helpful to use placeholders (also known as skeleton screens) to provide visual feedback to users while the actual data loads. By showing a simplified placeholder version of the list items, you keep the user engaged and avoid perceived lags. Libraries like react-native-skeleton-placeholder can help you implement this, creating a smoother experience, especially for slow network connections.

Speed Up React Native Apps by Reducing Application Size

Code Splitting and Bundle Optimization

Code splitting is a smart way to keep your app’s initial load time low by only loading the code necessary for the current screen. Using dynamic imports and code splitting techniques ensures that your app remains lightweight and fast, even as its complexity grows.

ProCoders Hack: Use the react-native-bundle-visualizer to analyze your bundle size and identify unnecessary or bulky modules. This tool helps you reduce the size of your JavaScript bundle, which directly impacts the app’s performance.

Minimize Third-Party Libraries

Third-party libraries can add significant weight to your app, increasing both bundle size and load times. Being selective about which libraries you include and removing unused dependencies will help keep your app lean.

ProCoders Hack: Whenever possible, opt for lightweight alternatives or implement custom solutions tailored to your app’s needs. This not only reduces the app size but also improves maintainability and performance.

React Native Performance Improvement: Memory Management

Avoid Memory Leaks

Memory leaks can slow down your app over time as unmounted components hold onto resources like event listeners or references. This often happens when components are not cleaned up properly after being removed from the DOM.

ProCoders Hack: To avoid this, always use cleanup functions in hooks like useEffect or component lifecycle methods like componentWillUnmount. These cleanups remove any event listeners, subscriptions, or side effects when components unmount, preventing memory bloat.

Clear Unnecessary State

Efficient state management plays a crucial role in memory usage. Holding onto unnecessary state can cause memory bloat, which impacts the app’s performance.

ProCoders Hack: For complex state management, consider using useReducer instead of useState. This helps manage state updates more efficiently, ensuring you don’t end up with redundant re-renders or stale data in memory.

How to Optimize React Native Apps: Optimize Animations

Use Native Driver for Animations

Smooth animations are vital for a good user experience, but animations can be resource-intensive. React Native offers the useNativeDriver option, which pushes animation calculations to the native side, allowing for smoother, more fluid animations without bogging down the JavaScript thread.

ProCoders Hack: For more complex animations, consider using the react-native-reanimated library. It’s optimized for performance and offers more flexibility, helping you deliver high-quality animations that don’t hurt performance.

Minimize Re-renders during Animations

Animations should run without interruption, but triggering re-renders while they’re in progress can cause frame drops, leading to choppy or inconsistent animations.

ProCoders Hack: Use InteractionManager.runAfterInteractions to delay any non-critical renders or actions until after the animations are complete. This keeps the animation smooth and avoids interfering with performance.

React Native App Optimization Tips: Efficient State Management

Use Context API or Redux Wisely

Efficient state management is key to ensuring your app doesn’t suffer from unnecessary re-renders. When using the Context API or Redux, it’s important to limit the number of components that subscribe to state changes. Too many subscriptions can lead to excessive re-renders and performance bottlenecks.

ProCoders Hack: In Redux, use selectors and only connect components that absolutely need access to the global store. This reduces the number of components that re-render whenever the state changes, ensuring a more efficient app.

Avoid Overusing Context

While the Context API is a powerful tool for managing state, overusing it can lead to performance degradation, especially when large component trees are re-rendered unnecessarily.

ProCoders Hack: Use React.memo and useContext selectively. Memoization helps you control which components should re-render, preventing unnecessary updates in your app.

Network Request Performance Optimization in React Native

Caching Network Requests

Frequent network requests can slow down your app and strain both performance and data usage. Caching API responses when appropriate can significantly improve performance, especially when dealing with static or rarely changing data.

ProCoders Hack: Libraries like react-query or axios-cache-adapter are great for handling request caching, ensuring that repeated network calls are avoided and previously fetched data is readily available without unnecessary delays.

Debouncing Input

Input fields, such as search bars, can cause performance issues if they trigger too many API requests while the user is typing. To prevent this, implement debouncing to delay making a request until the user stops typing, reducing the load on both the network and the app.

ProCoders Hack: You can implement debouncing easily with lodash.debounce or by creating custom hooks that delay actions, optimizing performance and improving the overall user experience.

ProCoders React Native Optimization Tips: Use Proguard for Android

Minify Code for Android

Proguard is a tool that helps optimize and shrink Android app code by removing unused code and resources, making your app lighter and more efficient. Enabling Proguard in your Android build process ensures that the bytecode is minimized, resulting in faster load times and better performance.

ProCoders Hack: Customize Proguard rules to control how code is minified without breaking functionality. This allows you to maintain full control over your app’s performance while still benefiting from optimized, minified code.

React Native Performance Tuning: Optimize Navigation

Use react-navigation Efficiently

React Navigation is widely used for managing app navigation, but if not optimized, it can lead to unnecessary re-renders and sluggish transitions.

ProCoders Hack: To improve navigation performance, use React.memo to memoize navigation screens and prevent redundant re-renders. Additionally, enable the lazy option in react-navigation to load screens only when they’re needed, reducing initial load times and improving overall app performance.

ProCoders’ Experience to Improve React Native Performance

For Roth River’s IoT development, we used React Native to create a cross-platform mobile app that connected whiskey lovers and distillers in a whole new way. With React Native, we built a single codebase that worked seamlessly on both iOS and Android, saving time and ensuring the app felt native to each platform.

Optimizing the app was key. We focused on things like efficient state management and smart image handling to ensure real-time updates flowed smoothly, giving users the experience they expected—whether tracking their whiskey’s aging process or making custom requests. Thanks to these optimizations, the app runs quickly and feels responsive, bringing Roth River’s vision to life while allowing us to deliver a polished product faster than anticipated.

React Performance Best Practices: Conclusion

optimizing your React Native app is essential to ensure a seamless user experience and efficient performance. By applying these hacks, such as minimizing re-renders, optimizing images, managing state wisely, and reducing memory consumption, you can significantly enhance your app’s speed and responsiveness. 

At ProCoders, we’ve seen firsthand how these strategies can transform a sluggish app into a high-performing, user-friendly product. With the right approach, you can unlock the full potential of React Native, delivering an app that both users and developers will love. Ready to optimize your app? Let ProCoders help you achieve top-tier performance!