Home >Web Front-end >JS Tutorial >Whats New in React : Exciting Features
React 19 has introduced a host of new features and improvements, making it even more powerful for building modern web applications. Here’s a roundup of the most notable updates, along with code examples to help you get started.
React 19 enhances concurrent rendering with better performance and reduced latency. The startTransition API allows for smoother updates.
import { startTransition } from 'react'; function handleClick() { startTransition(() => { // Trigger updates }); }
Automatic batching is now enabled by default, allowing multiple state updates to be batched together for better performance.
function handleClick() { setCount(count + 1); setValue(value + 1); }
Server components are now more powerful, with improved support for streaming and better integration with client components.
// serverComponent.js export default function ServerComponent() { return <div>Server-side content</div>; }
The new JSX transform eliminates the need to import React in every file that uses JSX.
// Old way import React from 'react'; function App() { return <div>Hello World</div>; } // New way function App() { return <div>Hello World</div>; }
React 19 introduces Suspense for data fetching, allowing components to suspend while data is being loaded.
import { Suspense } from 'react'; function DataFetchingComponent() { // Component code } function App() { return ( <Suspense fallback={<div>Loading...</div>}> <DataFetchingComponent /> </Suspense> ); }
Error boundaries now have better support for error handling in concurrent mode, improving the user experience when errors occur.
class ErrorBoundary extends React.Component { constructor(props) { super(props); this.state = { hasError: false }; } static getDerivedStateFromError() { return { hasError: true }; } componentDidCatch(error, info) { // Log error } render() { if (this.state.hasError) { return <h1>Something went wrong.</h1>; } return this.props.children; } }
React DevTools now includes more powerful features for debugging and profiling concurrent mode.
SSR in React 19 is more efficient, with better support for streaming and improved hydration.
import ReactDOMServer from 'react-dom/server'; const html = ReactDOMServer.renderToString(<App />);
Several new hooks are introduced, including useDeferredValue and useTransition, to handle more complex scenarios.
import { useDeferredValue, useTransition } from 'react'; function App() { const [startTransition, isPending] = useTransition(); const deferredValue = useDeferredValue(value); return <div>{deferredValue}</div>; }
The React Profiler has been updated to provide more insights into performance bottlenecks.
The Context API now has a simpler and more intuitive usage, making it easier to share data across components.
const MyContext = React.createContext(); function App() { return ( <MyContext.Provider value={/* value */}> {/* components */} </MyContext.Provider> ); }
React 19 comes with enhanced TypeScript support, including improved type inference and better integration.
New features in concurrent mode allow for smoother transitions and better responsiveness in your applications.
import { useTransition } from 'react'; function App() { const [isPending, startTransition] = useTransition(); return ( <button onClick={() => startTransition(() => { // update state })}> {isPending ? 'Loading...' : 'Click Me'} </button> ); }
Suspense now has improved support for nested components and more flexible configurations.
React 19 introduces new lifecycle methods to better manage component state and side effects.
StrictMode in React 19 offers better warnings and checks for deprecated APIs and potential issues.
The useReducer hook now has improved performance and usability for managing complex state logic.
const [state, dispatch] = useReducer(reducer, initialState);
React Native has received updates to align with React 19 features, improving compatibility and performance.
React 19 adds new concurrent features, like useDeferredValue, to better manage updates and performance.
The React documentation has been updated to include the latest features and best practices, making it easier to learn and use React 19.
React 19 brings a wealth of new features and improvements that enhance performance, usability, and development experience. By leveraging these updates, you can build more efficient and responsive applications with React.
Feel free to dive into these features and explore how they can benefit your projects!
The above is the detailed content of Whats New in React : Exciting Features. For more information, please follow other related articles on the PHP Chinese website!