Improving Performance with React's Experimental useTransition Hook in TypeScript

Introduction:

React is a popular JavaScript library for building user interfaces, and performance is a crucial aspect of creating responsive and engaging experiences for users. React's experimental Concurrent mode introduces the useTransition hook, which provides a way to manage resource fetching and component rendering while keeping the UI responsive. In this blog post, we will explore how to use the useTransition hook to optimizing performance in your React applications using TypeScript and arrow functions for components.

Prerequisites:

Before diving into the useTransition hook, make sure you have the following:

1. A basic understanding of React, its Hooks, and TypeScript.

2. A development environment with React Concurrent mode enabled. Please note that this feature is experimental and not yet recommended for production use.

Using the useTransition Hook:

The useTransition hook allows you to delay the rendering of a component while fetching data, providing a smoother user experience by preventing the UI from freezing or showing a loading state.

Let's see how it works with a simple example using a long array:

1. First, we need to import useTransition and Suspense from React:

    import React, { useState, Suspense } from 'react';
    import { useTransition } from 'react';
   

2. Let's create a simple component that fetches a long array of data:

    const fetchData = (): Promise<string[]> =>
      new Promise((resolve) =>
        setTimeout(
          () =>
            resolve(
              Array.from({ length: 1000 }, (_, i) => `Item ${i + 1}`)
            ),
          3000
        )
      );
   
    const DataComponent: React.FC = () => {
      const data = fetchData();
      return (
        <div>
          {data.map((item) => (
            <div key={item}>{item}</div>
          ))}
        </div>
      );
    };
   

3. Now, we will use the useTransition hook to manage the rendering of the DataComponent:

    const App: React.FC = () => {
      const [isPending, startTransition] = useTransition();
      const [showData, setShowData] = useState(false);
   
      const handleClick = () => {
        startTransition(() => {
          setShowData(!showData);
        });
      };
   
      return (
        <div>
          <button onClick={handleClick}>Toggle Data</button>
          <div>
            <Suspense fallback={<div>Loading...</div>}>
              {showData && <DataComponent />}
            </Suspense>
            {isPending && <div>Fetching data...</div>}
          </div>
        </div>
      );
    };
   
    export default App;
   

   In this example, we used the useTransition hook to manage the rendering of the DataComponent. The startTransition function allows us to delay the rendering of the component while the data is being fetched, and the isPending boolean lets us know if the transition is still in progress. The Suspense component wraps the DataComponent and displays a loading state until the data is ready.

Conclusion:

The experimental useTransition hook in React Concurrent mode provides a powerful way to manage resource fetching and component rendering, improving performance and providing a smoother user experience. While this feature is still experimental and not recommended for production use, it offers a glimpse into the future of React and the exciting possibilities it holds for building more responsive and engaging applications.