React useTransition Hook

React is a popular front-end JavaScript library that provides developers powerful tools for building dynamic and responsive user interfaces. One such tool is the useTransition hook, which was introduced in React 18. In this tutorial, we will explore what the useTransition hook is, how it works, and some use cases for it.

What is the useTransition hook?

The useTransition hook is a new feature introduced in React 18. It allows developers to control the timing of when a state update should be visible to the user. This can help improve the user experience by making UI updates more responsive and less jarring.

The useTransition hook takes two arguments: a configuration object and a state update function. The configuration object specifies the transition options, such as the transition duration and whether it should be animated. The state update function is the function that updates the state, and it can be any function that updates the state, such as the useState hook or a custom state management library.

How does the useTransition hook work?

When a state update function is called with the useTransition hook, React schedules the update but doesn’t immediately apply it. Instead, it returns a transition object that contains two properties: a boolean value that indicates whether the update has been applied yet, and a function that can be called to cancel the transition.

The transition object is then passed to the UI components that need to be updated along with the current state. The components can use this information to render the UI in a way that reflects the pending state update without actually updating the DOM.

Meanwhile, React continues to process other events and updates in the application, including user input and other state updates. After a short delay, if the current state has not changed, React applies the pending state update and signals the components to update the DOM to reflect the new state.

If the user takes an action that triggers another state update before the pending state update has been applied, the transition is cancelled, and the UI reverts to its previous state.

How to use the useTransition hook

Now that we’ve covered what the useTransition hook is and how it works, let’s look at how to use it in your React components.

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

function ExampleComponent() {
  const [count, setCount] = useState(0);
  const [startTransition, isPending] = useTransition({ timeoutMs: 1000 });

  function handleClick() {
    startTransition(() => {
      setCount(count + 1);
    });
  }

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={handleClick} disabled={isPending}>
        {isPending ? 'Updating...' : 'Update count'}
      </button>
    </div>
  );
}

In this example, we define a component that uses the useState hook to define a count state variable displayed in the UI. We then define a handleClick function that updates the count state variable when the user clicks a button.

To use the useTransition hook, we first import it from the 'react' library. We then call the useTransition hook and pass in a configuration object that specifies a timeout of 1000ms (1 second) for the transition. We also destructure the returned transition object to get the startTransition function and the isPending boolean.

Inside the handleClick function, we call the startTransition function and pass in the state update function that updates the count state variable. This schedules the state update but doesn’t immediately apply it.

We then use the isPending boolean to disable the button while the update is pending and display a message indicating the update status to the user.

After the timeout has elapsed, React applies the state update, and the UI is updated to reflect the new count value.

Why use the useTransition hook?

The useTransition hook can be used in various scenarios where you want to control the timing of state updates and improve the user experience. Some common use cases include:

  1. Animations: Animations can be resource-intensive and slow down the rendering of the UI. The useTransition hook can be used to delay the application of state updates until animations have been completed, allowing for smoother transitions and a more responsive user experience.
  2. Input feedback: When users interact with an input field, such as a text box, the UI can update rapidly and cause flickering. The useTransition hook can delay the application of state updates until the user has finished interacting with the input field, resulting in a smoother and more focused user experience.
  3. Loading indicators: When an application performs a complex task, such as fetching data from an API, it can be helpful to provide a loading indicator to let the user know that the application is working. The useTransition hook can delay the removal of the loading indicator until the data has been fetched and the UI is ready to update.

Conclusion

The useTransition hook is a powerful tool that can help improve the user experience of your React applications. By allowing you to control the timing of state updates, you can create smoother and more responsive UIs that are more focused on the user’s needs. Whether you’re building an animation-heavy interface, an input-driven app, or a data-intensive application, the useTransition hook is a feature worth exploring.

Scroll to Top