How to Effectively Use the React useId Hook in Your Apps

Every React developer has faced the challenge of maintaining unique component keys, particularly when working with dynamic lists. Fortunately, the useId Hook offers an elegant solution to this common challenge.

In this guide, you'll learn how to use the useId Hook. I'll cover everything by showing you how this powerful Hook can transform your approach to handling IDs in React applications.

What is React useId hook

Essentially, the useId hook lets us hook into the component instance to access the unique identifier for every component instance.

To make it simple, you can define it as this:

How the useId hook works

A core idea with React is that components are reusable. We should be able to render multiple instances of any component without issues. However, parts of the web platform weren't designed with reusability in mind. For example, id attributes must be globally unique!

How can we create reusable components while respecting this rule?

One solution is to add an id prop to the component, allowing developers to specify a unique value for each instance. This approach works, but it relies on developers remembering to provide unique values — a task that's more challenging than it seems!

Fortunately, the React team has created a new tool to help us out: the useId hook.

Inside our component, we can type:

import React from 'react';

function LoginForm() {
  const [username, setUsername] = React.useState('');
  const [password, setPassword] = React.useState('');

  // Retrieve this instance's unique ID from React 
  const id = React.useId();

  // Create element IDs using this unique ID
  const usernameId = `${id}-username`;
  const passwordId = `${id}-password`;
  
  return (
    <form className="login-form">
      <div>
        {/* Apply these IDs to the label and input */}
        <label htmlFor={usernameId}>
          Username:
        </label>
        <input
          type="text"
          id={usernameId}
          value={username}
          onChange={event => {
            setUsername(event.target.value);
          }}
        />
      </div>
      <div>
        <label htmlFor={passwordId}>
          Password:
        </label>
        <input
          type="password"
          id={passwordId}
          value={password}
          onChange={event => {
            setPassword(event.target.value);
          }}
        />
      </div>
      <button>
        Submit
      </button>
    </form>
  );
}

export default LoginForm;

Each instance of this component will receive a different value. For example, with 2 instances, the id variable equals :r0: in the first and :r1: in the second.

React hooks "hook into" the component instance. This ID lives on the instance and can be accessed during render. The value persists across renders. In that first instance, id will always equal :r0: on every render.

End

The useId hook is a powerful addition to React's toolkit that solves a common challenge in component development. By providing guaranteed unique identifiers that work seamlessly across server and client rendering, it eliminates the need for manual ID management and reduces the risk of accessibility issues.