In recent years, React has been working on improving its performance by introducing new features that allow for asynchronous rendering. Two of those features are React Suspense and Concurrent Mode. React Suspense allows for the components to wait for data to load before rendering, while Concurrent Mode allows for a more efficient use of resources by prioritizing which components should be rendered first. In this article, we will explore both features and understand how they work together to improve the user interface.

Understanding React Suspense and Concurrent Mode

React Suspense is a feature that allows for a component to display a fallback while waiting for data to load. This means that the component does not render until the data is ready. This feature allows for a better user experience since the user does not need to wait for the full page to load before seeing some content. Concurrent Mode, on the other hand, allows for a better use of available resources by prioritizing which components should be rendered first. This feature allows for a smoother and faster user interface.

Asynchronous UI Rendering: The Basics

Asynchronous UI rendering means that the user interface is not loaded all at once, but instead loaded in parts as the data becomes available. This allows for a faster and more efficient user experience. In traditional rendering, the whole page is loaded at once, which can cause delays and slow down the user experience. Asynchronous rendering is especially useful for websites or applications that rely on external data sources.

How React Suspense and Concurrent Mode Work Together

React Suspense and Concurrent Mode work together to provide a better user experience by allowing for asynchronous UI rendering. React Suspense allows for the components to wait for data to load before rendering, while Concurrent Mode prioritizes which components should be rendered first. This means that the components with the most priority are rendered first, providing a faster and smoother user interface.

Implementing Asynchronous UI Rendering with React Suspense and Concurrent Mode

To implement asynchronous rendering with React Suspense and Concurrent Mode, we need to wrap our components in a Suspense component. This component allows us to display a fallback while waiting for the data to load. We also need to use the useTransition hook to prioritize which components should be rendered first. This hook allows us to specify the timeout of the transition and which components should be rendered first.

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

function App() {
  const [startTransition, isPending] = useTransition({
    timeoutMs: 1000,
  });

  function handleClick() {
    startTransition(() => {
      // code to fetch data
    });
  }

  return (

      Fetch Data
      <Suspense fallback={Loading...}>
        {/* components to render */}

  );
}

Conclusion

React Suspense and Concurrent Mode allow for a better user experience by allowing for asynchronous UI rendering. React Suspense allows for the components to wait for data to load before rendering, while Concurrent Mode prioritizes which components should be rendered first. By implementing these features, we can create a faster and smoother user interface, especially for applications that rely on external data sources.