A Deep Dive into React's useId Hook

Aug 10, 2023

React, the popular JavaScript library for building user interfaces, is constantly evolving to offer more user-friendly features. One such feature is the useId Hook. But what is it, and how does it enhance the developer experience? Let's take a closer look.

What is the `useId` Hook?

At its core, useId is a React Hook designed to generate unique IDs. These IDs can then be passed on to accessibility attributes, making your website or app more accessible to all users, including those using assistive technologies.

const id = useId();

Why Use `useId`?

Generating unique IDs is essential in web development. Specifically, when it comes to accessibility attributes, such as aria-describedby, these IDs allow for the creation of relationships between different HTML tags.

For example, you might want to relate an input field to a descriptive paragraph. In raw HTML, this is done by manually setting an ID to the paragraph and referencing it in the input field. However, in React, this practice is discouraged. Components might render multiple times on a page, and IDs need to remain unique.

Enter useId. Instead of hardcoding IDs, this Hook lets you dynamically generate unique ones, ensuring that even if a component appears multiple times, there's no clash in IDs.

How to Implement `useId`?

It's straightforward. First, call the useId Hook at the top level of your component:

import { useId } from 'react'; function PasswordField( ) { const passwordHintId = useId(); // rest of the code }

Now, the generated ID can be passed on to various attributes:

<input type="password" aria-describedby={passwordHintId} /> <p id={passwordHintId}></p>

Do's and Don'ts of `useId`

DO call useId at the top level of your components. This ensures a fresh ID every time the component renders.
DON'T use useId for generating keys in lists. Instead, use data-specific values for your keys.
DO remember that useId is compatible with server rendering. This means that you need to ensure a consistent component tree on both the server and the client.
DON'T rely on incrementing counters as an alternative to useId. React guarantees that useId works seamlessly with server rendering, a promise hard to keep with manual counters.

Advanced Usage of `useId`

Related Elements: If you need to generate IDs for several connected elements, useId can help by providing a shared prefix. This avoids having to call the Hook for each individual element.
Distinct Prefixes: When dealing with multiple React apps on a single page, ensure the uniqueness of generated IDs by specifying a unique prefix for each app.

Conclusion

React's useId Hook is a powerful tool that not only enhances the accessibility of your apps but also streamlines the ID generation process. With its straightforward implementation and compatibility with server-side rendering, it's a must-use feature for developers aiming to build efficient and accessible React applications.

A Deep Dive into React's useId Hook

What is the useId Hook?

Why Use useId?

How to Implement useId?

Do's and Don'ts of useId