Exploring React 18 new hooks: useTransition, useDeferredValue and useOpaqueIdentifier

Introducing the New Hooks

React 18 introduces three new hooks: useTransition, useDeferredValue, and useOpaqueIdentifier. These hooks offer developers powerful tools for managing asynchronous rendering, optimizing performance, and enhancing accessibility within their applications.

1. useTransition

The useTransition hook enables smoother transitions during state updates, particularly when fetching asynchronous data or performing expensive calculations. It allows components to remain responsive and provide feedback to users while work is being done in the background.

import { useTransition } from 'react';

function MyComponent() {
  const [isPending, startTransition] = useTransition();

  const handleClick = () => {
    startTransition(() => {
      // Perform asynchronous task
      fetchData();
    });
  };

  return (
    <button onClick={handleClick} disabled={isPending}>
      {isPending ? 'Loading...' : 'Fetch Data'}
    </button>
  );
}

In this example, useTransition is used to initiate a transition before fetching data asynchronously. The startTransition function wraps the asynchronous task, ensuring that the UI remains responsive by deferring updates until the transition is complete.

2. useDeferredValue

The useDeferredValue hook is designed to optimize performance by deferring updating a part of the UI. It allows components to prioritize rendering based on the importance of the data being processed.

The syntax:

const deferredValue = useDeferredValue(value)

Like others react hooks, you should call useDeferredValue at the top level of your component to get a deferred version of that value. That's the hook rule.

function App() {
  const [text, setText] = useState('');
  const deferredText = useDeferredValue(text);

  return (
    <>
      <input value={text} onChange={e => setText(e.target.value)} />
      <SlowList text={deferredText} />
    </>
  );
}

Make sure that the SlowList component need to using react.memo to prevent re-render with the same prop:

const SlowList = memo(function SlowList({ text }) {
  // ...
});

In this example, useDeferredValue is used to defer the text state variable (deferredText) to the SlowList component, updates to the UI rendered by SlowList will be deferred, prioritizing other interactions in the meantime. This can help improve the responsiveness and performance of the application, especially when dealing with complex UI components or large datasets. You guys can read more details in this post: https://www.sharetolearn.pro/articles/mastering-async-rendering-with-usedeferredvalue-in-react

3. useOpaqueIdentifier

The useOpaqueIdentifier hook provides a way to generate opaque identifiers that are both unique and secure. This is particularly useful for ensuring accessibility and privacy when managing sensitive data within components.

import { useOpaqueIdentifier } from 'react';

function MyComponent() {
  const id = useOpaqueIdentifier();

  return <div id={id}>Sensitive Content</div>;
}

In this example, useOpaqueIdentifier generates a unique and secure identifier that can be used to associate sensitive content with a component. This helps prevent unauthorized access and ensures compliance with accessibility guidelines.

Conclusion

The new hooks introduced in React 18 offer powerful capabilities for managing state, optimizing performance, and enhancing accessibility within applications. By leveraging these hooks, developers can create more responsive and efficient user interfaces, ultimately improving the overall user experience. As React continues to evolve, these hooks provide valuable tools for building modern web applications that are both performant and accessible.