React - React Suspense

Using React Suspense for data fetching

React Suspense is a powerful feature that allows you to handle asynchronous operations like data fetching in a more declarative way. It enables you to show a fallback UI while the data is being loaded, making your application feel more responsive. This tutorial covers the key concepts and usage of React Suspense for data fetching.

Setting Up React Suspense

To use React Suspense for data fetching, you need to create a resource that fetches data and wraps it in a Suspense component with a fallback UI. Here's a simple example of setting up Suspense for data fetching:

// Example of a data fetching function
const fetchData = () => {
    return new Promise((resolve) => {
        setTimeout(() => {
            resolve('Data fetched!');
        }, 2000);
    });
};

// Creating a resource for Suspense
const createResource = (promise) => {
    let status = 'pending';
    let result;
    let suspender = promise.then(
        (res) => {
            status = 'success';
            result = res;
        },
        (err) => {
            status = 'error';
            result = err;
        }
    );
    return {
        read() {
            if (status === 'pending') {
                throw suspender;
            } else if (status === 'error') {
                throw result;
            } else if (status === 'success') {
                return result;
            }
        },
    };
};

const resource = createResource(fetchData());
                

Using Suspense in Your Component

Wrap your component with the Suspense component and provide a fallback UI to display while the data is being fetched:

import React, { Suspense } from 'react';

// Creating a component that reads data from the resource
const DataComponent = () => {
    const data = resource.read();
    return <div>{data}</div>;
};

const App = () => {
    return (
        <div>
            <h1>React Suspense Demo</h1>
            <Suspense fallback="Loading...">
                <DataComponent />
            </Suspense>
        </div>
    );
};

export default App;
                

Combining Suspense with Concurrent Mode

React's concurrent mode works well with Suspense, allowing you to manage asynchronous rendering more effectively. Concurrent mode is an experimental feature that can be enabled in your application:

// Enabling concurrent mode in index.js
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

ReactDOM.createRoot(document.getElementById('root')).render(<App />);
                

Best Practices

Here are some best practices for using React Suspense in your applications:

• Use Suspense for data fetching to improve the user experience with fallback UIs.
• Combine Suspense with concurrent mode for better asynchronous rendering management.
• Ensure that your data fetching functions handle errors gracefully to avoid breaking the UI.
• Test your Suspense components thoroughly to ensure they work correctly under different loading conditions.

Summary

In this tutorial, you learned about using React Suspense for data fetching. React Suspense allows you to handle asynchronous operations in a declarative way, providing a better user experience with fallback UIs while data is being loaded. By setting up Suspense, using it in your components, and following best practices, you can effectively manage data fetching in your React applications.