Introduction to the useTransition Hook

The useTransition hook is a new addition to the React family of hooks that allows developers to perform animations while waiting for an update to be committed. It is currently in beta and is subject to change, but it is a useful tool for adding polish to your React applications.

To use the useTransition hook, you will first need to make sure that you are using a version of React that includes it. As of the time of writing, the current version of React is 17.0.0-beta.3, which includes the useTransition hook.

Once you have a compatible version of React, you can use the useTransition hook by importing it from the react package.

import { useTransition } from 'react';

The useTransition hook takes two arguments: an item that you want to transition, and a configuration object that specifies the details of the transition.

Here is an example of using the useTransition hook to transition the color of a div element:

function MyComponent() {
  const [color, setColor] = useState('red');
  const [startTransition, isPending] = useTransition({
    timeoutMs: 3000,
  });

  function handleClick() {
    startTransition(() => {
      setColor('blue');
    });
  }

  return (
    <div style={{ color }}>
      <button onClick={handleClick}>Change Color</button>
    </div>
  );
}

In this example, when the button is clicked, the handleClick function is called, which triggers the startTransition function. The startTransition function takes a function as an argument, which is the update that you want to perform. In this case, the update is to change the color of the div element to blue.

The useTransition hook returns a tuple with two values: a startTransition function, and a boolean value isPending that indicates whether a transition is currently in progress. You can use the isPending value to apply styles or behaviors to your component while the transition is happening.

For example, you could use the isPending value to apply a spinner or loading indicator while the transition is in progress:

function MyComponent() {
  const [color, setColor] = useState('red');
  const [startTransition, isPending] = useTransition({
    timeoutMs: 3000,
  });

  function handleClick() {
    startTransition(() => {
      setColor('blue');
    });
  }

  return (
    <div style={{ color }}>
      {isPending ? (
        <div>Loading...</div>
      ) : (
        <button onClick={handleClick}>Change Color</button>
      )}
    </div>
  );
}

The useTransition hook also supports a number of configuration options that allow you to customize the behavior of the transition. These options can be passed in the second argument to the useTransition hook.

For example, you can use the timeoutMs option to specify the length of time that the transition should take. You can also use the maxDurationMs option to specify the maximum duration of the transition, in case it takes longer than expected.

Here is an example of using the maxDurationMs option to ensure that the transition does not take longer than 500 milliseconds:

const [startTransition, isPending] = useTransition({
  timeoutMs: 3000,
  maxDurationMs: 500,
});

Another option that you can use is the suspense option, which allows you to specify a React Suspense component as the parent of your component. When the useTransition hook is in a Suspense component, it will cause the component to suspend rendering until the transition is complete. This can be useful for optimizing the performance of your application by avoiding rendering expensive components until they are needed.

Here is an example of using the suspense option to wrap a component in a Suspense component:

const [startTransition, isPending] = useTransition({
  timeoutMs: 3000,
  suspense: <MySuspenseComponent />,
});

There are many other options and features available with the useTransition hook, such as the ability to cancel or skip transitions, or to specify different styles for different stages of the transition. Be sure to check out the React documentation for more information on how to use these features.

Conclusion

In summary, the useTransition hook is a powerful tool for adding transitions and animations to your React components. It is easy to use and provides a lot of flexibility and customization options. If you are looking to add some polish to your React application, consider giving the useTransition hook a try.