Combining suspense with React Native

16 Oct 2023

React Native is a popular framework for building cross-platform mobile applications using React. One of the key features introduced in React 16.6 is the Suspense component, which allows us to handle loading states and async rendering more seamlessly. In this blog post, we’ll explore how to combine Suspense with React Native to create smoother user experiences in our mobile apps.

Introduction
What is Suspense?
Using Suspense in React Native
Error Boundaries with Suspense
Lazy Loading Components
Conclusion

Introduction

React Native enables us to write mobile apps using JavaScript and React. It uses native components and renders them using the platform’s rendering APIs, resulting in high-performance and native-like user interfaces. However, handling asynchronous data loading and showing loading states can be challenging without the proper tools.

That’s where Suspense comes in. Introduced in React 16.6, Suspense provides a simple and declarative way to handle loading states and async rendering in our React components. It allows us to specify fallback UI while our data is loading, making the user experience smoother and more engaging.

What is Suspense?

Suspense is a React component that allows us to specify a fallback UI while we load data asynchronously. It “suspends” rendering the component tree until the data is ready, and then it displays the resolved content. It simplifies handling asynchronous operations in our components and provides a better user experience.

Using Suspense in React Native

To use Suspense in React Native, we need to ensure we are using React Native version 0.59 or higher, as Suspense was introduced in React 16.6. We can start by wrapping our top-level component with the Suspense component and specifying a fallback UI using the fallback prop.

import React, { Suspense } from 'react';
import { View, ActivityIndicator } from 'react-native';

const App = () => (
  <Suspense fallback={<View style=><ActivityIndicator /></View>}>
    {/* Your app components */}
  </Suspense>
);

export default App;

In the above example, we use the ActivityIndicator component to show a loading spinner as the fallback UI while our components are being loaded.

Error Boundaries with Suspense

Error boundaries are special React components that catch JavaScript errors anywhere in their child component tree and display fallback UI instead of crashing the whole app. We can combine error boundaries with Suspense to handle errors during async rendering gracefully.

To create an error boundary, we define a new component that overrides the componentDidCatch lifecycle method. Suspense automatically invokes this method if any of its children throw an error.

import React, { Component } from 'react';

class ErrorBoundary extends Component {
  state = {
    hasError: false,
    error: null,
  };

  componentDidCatch(error) {
    this.setState({ hasError: true, error });
  }

  render() {
    if (this.state.hasError) {
      return <ErrorFallback />;
    }

    return this.props.children;
  }
}

export default ErrorBoundary;

Using the ErrorBoundary component with Suspense allows us to gracefully handle errors during async rendering in our React Native apps.

Lazy Loading Components

Another great use case of Suspense in React Native is lazy loading components. With lazy loading, we can split our app’s code into smaller chunks and load them only when needed, reducing the initial bundle size and improving app performance.

React Native Lazy is a library that provides an easy way to lazily load components in React Native using Suspense. Here’s an example of how to use it:

import React, { lazy } from 'react';
import { Suspense } from 'react-native';
import Loading from './Loading';

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

const App = () => (
  <Suspense fallback={<Loading />}>
    <LazyComponent />
  </Suspense>
);

export default App;

In the above example, we use the lazy function from React to lazily load the LazyComponent module asynchronously. While the module is loading, the Loading component is displayed as the fallback UI.

Conclusion

Suspense is a powerful feature introduced in React 16.6 that allows us to handle loading states and async rendering in a more elegant and declarative way. By combining Suspense with React Native, we can enhance the user experience of our mobile apps and create smoother interactions.

In this blog post, we explored how to use Suspense in React Native, handle errors using error boundaries, and lazily load components. By leveraging these features, we can build more performant and responsive mobile applications with React Native.

#reactnative #suspense

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