In a React application, it is common to have components that fetch data asynchronously. While waiting for the data to be loaded, we can use suspense to render a fallback UI, such as a progress bar, to provide feedback to the user.
To implement a progress bar with suspense in React, follow these steps:
Step 1: Install the necessary packages
First, make sure you have the necessary packages installed. We will be using the react-dom and react-router-dom packages for this example. Install them by running the following command:
npm install react-dom react-router-dom
Step 2: Create a progress bar component
Create a new file called ProgressBar.js and add the following code:
import React from 'react';
const ProgressBar = () => {
return (
<div>
<h3>Loading...</h3>
<progress max="100" />
</div>
);
};
export default ProgressBar;
This component renders a simple progress bar with the text “Loading…” and an HTML progress element.
Step 3: Update your main component
In your main component where you fetch the data, import the lazy and Suspense components from React and the ProgressBar component. Wrap the component that fetches the data inside a Suspense component and provide the fallback prop with the ProgressBar component.
import React, { lazy, Suspense } from 'react';
import { BrowserRouter as Router, Route, Switch } from 'react-router-dom';
import ProgressBar from './ProgressBar';
const MyComponent = lazy(() => import('./MyComponent'));
const App = () => {
return (
<Router>
<Suspense fallback={<ProgressBar />}>
<Switch>
<Route path="/" component={MyComponent} />
</Switch>
</Suspense>
</Router>
);
};
export default App;
In this example, we are using the lazy function to import the component that fetches the data asynchronously. The fallback prop of the Suspense component is set to the ProgressBar component, which will be rendered while the data is being fetched.
Step 4: Test the progress bar
Run your application and navigate to the route where the component that fetches the data is rendered. You should see the progress bar being shown while the data is being loaded. Once the data is loaded, the component will be rendered.
Conclusion
By using suspense in React, we can provide a better user experience by showing a progress bar or any other type of fallback UI while waiting for data to be loaded asynchronously. This helps to communicate to the user that something is happening and reduces the perceived loading time.