How to Improve Performance of Your React Native App?
Gauri Pawar

Over the last couple of years, React Native Development has taken the app development world by storm, and with good reason. It turned out to be the magic wand that enabled businesses to rationalize costs, get their ideas to the market faster and create a well-optimized and responsive user experience. The impact of these advantages has been large enough to sway big brands like Walmart, Bloomberg, Tesla, Uber, and Skype towards React Native app development.

But smaller businesses and companies can benefit just as much from React Native’s inherent advantages. We’ve already talked about its benefits and how to create your first app using React Native. But building your first React Native is likely to be a trial and error process. Building an app, testing it, optimizing it, launching it and incorporating changes into it after feedback is a never-ending process and the key to creating a consistent user experience. However, there are a few things you can do from the get-go to enhance the performance of your app. Here are 10 ways to get the most out of your first React Native app.

  1. Include only necessary features– A long feature list is nice to have. But it can also cause your app to suffer slow display times. In order of importance, swift performance should always come before a rich feature list. You can achieve that by removing all unnecessary data, controls, animations, tabs, and navigations from your React Native application. Every one of those features has the potential to stretch your app’s display times by a few seconds and cause a cluttered user experience. A lean architecture, on the other hand, will help your app fly!
  2. Focus on app launch time – If your app is new, you’d want as many people as possible to give it a try. But if it suffers from slow launch time, users might not even give your app a chance. A common culprit behind this problem is object.finalize. These finalizers occupy a thread and can lead to error messages that warn of your application running out of memory; even when there’s enough free memory. This can slow down your React Native app launch times. To avoid this, do not run important components on the main thread and stay away from Object Finalizers.
  3. Make the app lightweight – A smaller footprint is a proven way of improving the performance of your React Native application. Unfortunately, that is also what makes it a challenge and something most first-time developers get wrong. That’s chiefly down to the fact that a JavaScript application usually requires the use of third-party libraries and native components; both of which balloon up to the application size. You can overcome this hurdle by including only important components, optimizing those components, reducing the size of graphics and using an optimizer like ProGuard.
  4. Render one service at a time – This is important because React Native supports only one thread at a time. So, if you were to render multiple services simultaneously, your React Native app is likely to crash or suffer a slowdown. The solution lies in rendering only one service at a time. It’s a drawback, yes, but a minor offset when you consider the numerous benefits of React Native development.
  5. Simplify JSON structure – A mobile phone fetches data from far-flung URLs and more often than not, this data is contained within a JSON structure. This is an issue since JavaScript, which is what React Native uses, applications are notorious for retrieving JSON data slowly. You can prevent this slow download from hampering your React Native app performance by simplifying the JSON data structure.
  6. Plug memory leaks – Memory leakage in Android applications is a known issue and happens when too many processes lurk in the background. One of the most effective ways to safeguard your React Native app from memory leaks is to use scrolling lists like SectionList, VirtualList or FlatList, instead of ListView.
  7. Reduce bridge load – In a React Native application, the JavaScript side connects with the Native side through a bridge. If this bridge is cluttered with excess load, the performance of your React Native suffers. Reducing excess bridge load helps achieve effective communication, which in turn improves overall performance. A time-tested way of doing so is by examining the dependability of an open source library before using it. You can also prevent the movement of components on the main thread since they use heavy message queues to communicate with the Native side.
  8. Optimize images – Image caching helps load images quickly and should be used in React Native to accelerate image downloading. On the flipside, the feature is available only for iOS, and not Android. However, there are a bunch of other things you can do to help images load quickly and without errors in your React Native app. These include using images that are simple for your application to deal with, converting images to PNG prior to first use, reducing the size of those images, saving images in the WebP format, etc. These seemingly minor details can have a massive impact on your app’s loading speed.
  9. Re-render only when necessary – This is a common pitfall that first time React Native Developers should avoid. A needless or repeated rending of components can have a debilitating effect on your app’s performance. The workaround for this issue is rather simple; implement the ‘shouldComponentUpdate’ function. This ensures your app renders a component only when necessary.
  10. Speed up app navigation – Slow and clunky navigation mars the user experience of your React Native app. You can get rid of this by eliminating the console.log when merging your map library with the app. This prevents two things that are directly responsible for slowing down your app’s navigation, i) saving information in the Xcode, and ii) automatically updating the maps. As an aside, this also highlights the negative impact that technical debt has on an app’s navigation. The focus, as such, should always be on minimizing technical debt accumulation. For instance, using FlatList to display a long list of your items instead of the unwieldy ListView.

React Native Development can be rewarding in multiple aspects. However, the task doesn’t end there as a React Native app needs optimization, just like any other Native application. By implementing these optimization techniques, you can ensure your first React Native app is also your best-performing one.

POSTED IN: May 14, 2019 Gauri Pawar

Post Comments (1)

  1. Such a great article. You are right, nowadays React Native search is more than Android or iOS search on Google. React Native is the best platform for mobile app development. So many advantages of React native than other technology. React Native is growing popular day by day. Everyone wants to develop their apps in a React-Native platform because one app can run on cross-platform. Its reduce code, time efficiency, good performance and fast.

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