Boost Your React Performance with useDeferredValue Hook: An Example-driven Guide
Tags: webdev, javascript, react, tutorial
Published: 2023-04-04 16:25:43

One of the most popular JavaScript frameworks is React, which provides a number of hooks to make the process of creating online apps easier. `UseDeferredValue` hook is one such hook. The speed of the application can be enhanced by using this hook to delay state updates until the user has finished engaging with it. The `useDeferredValue` hook, its advantages, and how to use it in your React application will all be covered in this essay.


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/tbblosu6wkenlrh2nfwg.png)

## Benefits of useDeferredValue Hook

The useDeferredValue hook allows you to defer the updates of state changes until the user is done interacting with the application. This approach has several benefits, including:

1. **Improving application performance**: By deferring state updates, you can avoid unnecessary re-renders, which can significantly improve the performance of your application.

2. **Smoother user experience**: By delaying updates until the user is done interacting with the application, you can provide a smoother user experience, with fewer interruptions or unexpected changes.

3. **More efficient rendering**: With deferred updates, React can batch multiple updates into a single render pass, which can make rendering more efficient and reduce the overall workload on your application.

## How to use the useDeferredValue Hook?

Utilizing the useDeferredValue method is not too difficult. You need to perform these actions in order to use it:

1. **Import the hook**: To use the useDeferredValue hook, you need to import it from the React library.

2. **Create a deferred state**: You can create a deferred state by calling the useDeferredValue hook and passing in the initial value.

3. **Use the deferred state**: You can use the deferred state just like any other state in your application, but React will defer updates to it until the user is done interacting with the application.

Here is an example of how to use the useDeferredValue hook in a React component:

Let's assume your React application has a search bar component that enables users to look for things in a list. You want to update the search results in real-time as the user enters a question into the search box, but you don't want to update the search results until the user has completed typing to prevent pointless re-renders. Here's an illustration of how to accomplish this using the useDeferredValue hook:


```javascript
import React, { useState } from 'react';
import { useDeferredValue } from 'react';

function SearchBar({ items }) {
  const [query, setQuery] = useState('');
  const deferredQuery = useDeferredValue(query, { timeoutMs: 500 });

  const searchResults = items.filter((item) =>
    item.name.toLowerCase().includes(deferredQuery.toLowerCase())
  );

  function handleQueryChange(event) {
    setQuery(event.target.value);
  }

  return (
    <div>
      <input type="text" value={query} onChange={handleQueryChange} />
      <ul>
        {searchResults.map((item) => (
          <li key={item.id}>{item.name}</li>
        ))}
      </ul>
    </div>
  );
}

```

In this example, we create a new state value called query using the useState hook. We also create a deferred state value called `deferredQuery` using the `useDeferredValue` hook, and we initialize it with the same initial value as query. We pass an options object to `useDeferredValue` to specify a timeout of 500 milliseconds, which means that updates to `deferredQuery` will be deferred for at least 500 milliseconds after the last change to query.

We use the `searchResults` variable to filter the items array based on the `deferredQuery`. The searchResults variable is re-computed whenever `deferredQuery` changes, which will happen after a short delay once the user has finished typing.

In the `handleQueryChange` function, we update the query state value whenever the user types into the search bar. This will cause `deferredQuery` to be updated, but the actual update will be deferred until the user has finished typing for at least 500 milliseconds.

By using the `useDeferredValue` hook in this way, we can provide real-time search results without causing unnecessary re-renders and without making the user interface feel sluggish or unresponsive.

## Conclusion

The useDeferredValue hook is a powerful tool for improving the performance and user experience of your React applications. By deferring state updates until the user is done interacting with the application, you can reduce the number of unnecessary re-renders, provide a smoother user experience, and make rendering more efficient. If you are building a React application, consider using the useDeferredValue hook to improve your application's performance and user experience.