React Suspense is a feature introduced in React to simplify the handling of asynchronous operations like data fetching or code splitting. Here's a basic guide on how to use it:
-
Code Splitting with
React.lazy
:- Use
React.lazy
to dynamically import a component. This helps split your code into chunks that are loaded only when needed.
- Use
const SomeComponent = React.lazy(() => import('./SomeComponent'));
-
Wrap with
<Suspense>
Component:- Wrap the lazily loaded component with the
<Suspense>
component. - Provide a fallback UI to display while the component is being loaded.
- Wrap the lazily loaded component with the
import React, { Suspense } from 'react';
function MyComponent() {
return (
<Suspense fallback={<div>Loading...</div>}>
<SomeComponent />
</Suspense>
);
}
-
Handling Data Fetching:
- For data fetching, you can use libraries like Relay or others that support Suspense.
- Wrap the component that performs data fetching inside
<Suspense>
. - The fallback will be displayed until the data fetching is complete.
-
Error Boundaries:
- Use error boundaries to handle errors in asynchronous code. Suspense boundaries only handle loading states, not errors.
- Wrap your Suspense component in an error boundary to catch and handle errors gracefully.
-
Server Side Rendering (SSR):
- If using SSR, ensure your server-rendering environment supports Suspense.
- Libraries like Next.js have built-in support for Suspense with SSR.
-
Use with Concurrent Mode (Experimental):
- Suspense works best with React's Concurrent Mode, which is still experimental.
- Concurrent Mode allows for more fine-grained control over the rendering process, improving performance for complex applications.
-
Testing:
- When writing tests for components using Suspense, make sure to mock the loading state and test the fallback UI.
- Also, test the loaded state to ensure the component renders ``correctly after the asynchronous operation completes.
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