React · Hooks (Comprehensive)

useId Hook

Master useId to generate unique IDs that are stable across server and client rendering - essential for accessibility and form inputs.

Find videos you like?

Save to resource drawer for future reference!

What is useId?

Generate unique IDs for accessibility

useId is a Hook that generates a unique ID that is stable across server and client renders. It's perfect for connecting HTML elements with htmlFor attributes, ARIA attributes, and accessibility needs.

Basic Syntax

// Generate unique ID

const id = useId();

// Use in JSX

Returns:String ID like ":r1:", ":r2:", etc.

Stable:Same ID on server and client

Server-Side Safe

• Works with SSR/SSG
• No hydration mismatches
• Stable across renders
• Predictable generation

Accessibility Focus

• Form label connections
• ARIA attribute linking
• Screen reader support
• Semantic HTML relationships

SSR Compatible!

Unlike Math.random() or counters, useId generates the same ID on server and client, preventing hydration errors!

When to Use useId

Essential use cases for unique IDs

Form Accessibility

Connect labels with inputs using htmlFor and id attributes for screen readers

ARIA Attributes

Link descriptive elements with interactive elements using aria-labelledby or aria-describedby

Component Libraries

Generate unique IDs for reusable components that need internal element connections

💡 Pro Tip

Use useId whenever you need to connect HTML elements programmatically. Never use Math.random() or counters for IDs in React!

Step-by-Step Guide

Learn useId progressively

Step 1: Generate an ID

Call useId() to generate a unique ID that will be stable across server and client renders.

//Generate unique ID in component

import { useId } from 'react';

function MyInput() {}

const id = useId();

// ID will be something like ":r1:"

console.log(id); // ":r1:"

}

Pro Tip

Each useId() call generates a unique ID. Multiple calls in the same component will produce different IDs.

Step 2: Connect Form Elements

Use the generated ID to connect labels with inputs using htmlFor and id attributes.

//Connect label and input

function NameInput() {}

const id = useId();

return (

Name:

</label>

</>

);

}

Accessibility Win!

Screen readers will now announce "Name, edit text" when users focus on the input field.

Step 3: Use with ARIA Attributes

Connect descriptive elements with interactive elements using ARIA attributes for enhanced accessibility.

//Connect error message with input

function ValidatedInput() {}

const inputId = useId();

const errorId = useId();

return (

<div>

<input

id=<span className="text-green-600">{inputId}</span>

aria-describedby=<span className="text-green-600">{errorId}</span>

<div id=<span className="text-green-600">{errorId}</span> >

Error message

</div>

);

}

Screen Reader Magic

Screen readers will announce the input and then read the associated error message automatically.

Step 4: Create Reusable Components

Build reusable components that generate their own unique IDs, preventing conflicts when used multiple times.

//Reusable checkbox component

function Checkbox({ children, disabled }) {}

const id = useId();

return (

<input id=<span className="text-green-600">{id}</span> type="checkbox" />

{children}

</label>

</div>

);

}

// Safe to use multiple times!

<Checkbox>Option 1</Checkbox>

<Checkbox>Option 2</Checkbox>

No ID Conflicts!

Each Checkbox instance gets its own unique ID, preventing conflicts and ensuring proper accessibility.

Step 5: Best Practices

Follow these guidelines to use useId effectively and avoid common pitfalls.

//DO: Use for accessibility

const id = useId();

<label htmlFor=<span className="text-green-600">{id}</span>>Label</label>

//DON'T: Use for CSS selectors

<div id=<span className="text-green-600">{id}</span> className="my-component">

//DO: Use in component libraries

function CustomInput() {}

const id = useId();

//DON'T: Use for list keys

items.map(item => (

<div key=<span className="text-green-600">{useId()}</span>> // Wrong!

))

Golden Rule

Use useId only for connecting HTML elements. For list keys, use stable identifiers from your data.

Example: Accessible Form Component

Building a complete accessible form with useId

Accessible Form with useId

Complete form with proper accessibility connections

Frontend

function FormField({ label, type = 'text', error, required = false }) {
  const id = useId();
  const errorId = useId();

  return (
    <div className="form-field">
      <label htmlFor={id}>
        {label}
        {required && <span className="required">*</span>}
      </label>
      <input
        id={id}
        type={type}
        aria-describedby={error ? errorId : undefined}
        aria-invalid={error ? 'true' : 'false'}
        required={required}
      />
      {error && (
        <div id={errorId} className="error-message" role="alert">
          {error}
        </div>
      )}
    </div>
  );
}

function SignUpForm() {
  const [formData, setFormData] = React.useState({
    name: '',
    email: '',
    password: ''
  });
  const [errors, setErrors] = React.useState({});

  const validateForm = () => {
    const newErrors = {};
    
    if (!formData.name.trim()) {
      newErrors.name = 'Name is required';
    }
    
    if (!formData.email.trim()) {
      newErrors.email = 'Email is required';
    } else if (!/\S+@\S+\.\S+/.test(formData.email)) {
      newErrors.email = 'Email is invalid';
    }
    
    if (!formData.password) {
      newErrors.password = 'Password is required';
    } else if (formData.password.length < 8) {
      newErrors.password = 'Password must be at least 8 characters';
    }
    
    setErrors(newErrors);
    return Object.keys(newErrors).length === 0;
  };

  const handleSubmit = (e) => {
    e.preventDefault();
    if (validateForm()) {
      alert('Form submitted successfully!');
      setFormData({ name: '', email: '', password: '' });
      setErrors({});
    }
  };

  const handleChange = (field) => (e) => {
    setFormData(prev => ({ ...prev, [field]: e.target.value }));
    // Clear error when user starts typing
    if (errors[field]) {
      setErrors(prev => ({ ...prev, [field]: '' }));
    }
  };

  return (
    <div className="container">
      <div className="form-header">
        <h1>🔐 Create Account</h1>
        <p>Join us today! All fields are required.</p>
      </div>

      <form onSubmit={handleSubmit} className="signup-form">
        <FormField
          label="Full Name"
          value={formData.name}
          onChange={handleChange('name')}
          error={errors.name}
          required
        />
        
        <FormField
          label="Email Address"
          type="email"
          value={formData.email}
          onChange={handleChange('email')}
          error={errors.email}
          required
        />
        
        <FormField
          label="Password"
          type="password"
          value={formData.password}
          onChange={handleChange('password')}
          error={errors.password}
          required
        />

        <div className="form-actions">
          <button type="submit" className="submit-btn">
            Sign Up
          </button>
        </div>
      </form>

      <div className="accessibility-info">
        <h2>♿ Accessibility Features</h2>
        <ul>
          <li>✅ All form fields have proper label connections</li>
          <li>✅ Error messages are announced by screen readers</li>
          <li>✅ Required fields are clearly marked</li>
          <li>✅ Form validation provides helpful feedback</li>
          <li>✅ Unique IDs prevent conflicts</li>
        </ul>
      </div>
    </div>
  );
}

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(<SignUpForm />);

Live Preview

Loading preview...

Key Concepts

Understanding useId fundamentals

Unique Generation

Each useId() call generates a unique identifier that won't conflict with other IDs.

SSR Compatible

IDs are stable across server and client rendering, preventing hydration mismatches.

Performance

Lightweight and fast - no performance overhead compared to manual ID generation.

Best Practices

Do's and Don'ts for useId

✅ Do This

Use for form label connections
Use with ARIA attributes
Create reusable components
Use in component libraries

❌ Avoid This

Don't use for CSS selectors
Don't use for list keys
Don't use for data attributes
Don't rely on ID format

Accessibility First!

useId is your best friend for building accessible React components. Always use it for connecting HTML elements!

Previous Topic

useDebugValue Hook

Debug custom hooks in React DevTools, create custom debug labels, and improve development experience.

Next Topic

useSyncExternalStore

Subscribe to external stores, third-party state management, and concurrent rendering compatibility.

Ask a Question

Have a question about useId Hook? Ask our AI assistant.

🔐 Login to use AI Assistant

React · Hooks (Comprehensive)

useId Hook

Master useId to generate unique IDs that are stable across server and client rendering - essential for accessibility and form inputs.

Find videos you like?

Save to resource drawer for future reference!

What is useId?

Generate unique IDs for accessibility

Basic Syntax

// Generate unique ID

const id = useId();

// Use in JSX

Returns:String ID like ":r1:", ":r2:", etc.

Stable:Same ID on server and client

Server-Side Safe

• Works with SSR/SSG
• No hydration mismatches
• Stable across renders
• Predictable generation

Accessibility Focus

• Form label connections
• ARIA attribute linking
• Screen reader support
• Semantic HTML relationships

SSR Compatible!

Unlike Math.random() or counters, useId generates the same ID on server and client, preventing hydration errors!

When to Use useId

Essential use cases for unique IDs

Form Accessibility

Connect labels with inputs using htmlFor and id attributes for screen readers

ARIA Attributes

Link descriptive elements with interactive elements using aria-labelledby or aria-describedby

Component Libraries

Generate unique IDs for reusable components that need internal element connections

💡 Pro Tip

Use useId whenever you need to connect HTML elements programmatically. Never use Math.random() or counters for IDs in React!

Step-by-Step Guide

Learn useId progressively

Step 1: Generate an ID

Call useId() to generate a unique ID that will be stable across server and client renders.

//Generate unique ID in component

import { useId } from 'react';

function MyInput() {}

const id = useId();

// ID will be something like ":r1:"

console.log(id); // ":r1:"

}

Pro Tip

Each useId() call generates a unique ID. Multiple calls in the same component will produce different IDs.

Step 2: Connect Form Elements

Use the generated ID to connect labels with inputs using htmlFor and id attributes.

//Connect label and input

function NameInput() {}

const id = useId();

return (

Name:

</label>

</>

);

}

Accessibility Win!

Screen readers will now announce "Name, edit text" when users focus on the input field.

Step 3: Use with ARIA Attributes

Connect descriptive elements with interactive elements using ARIA attributes for enhanced accessibility.

//Connect error message with input

function ValidatedInput() {}

const inputId = useId();

const errorId = useId();

return (

<div>

<input

id=<span className="text-green-600">{inputId}</span>

aria-describedby=<span className="text-green-600">{errorId}</span>

<div id=<span className="text-green-600">{errorId}</span> >

Error message

</div>

);

}

Screen Reader Magic

Screen readers will announce the input and then read the associated error message automatically.

Step 4: Create Reusable Components

Build reusable components that generate their own unique IDs, preventing conflicts when used multiple times.

//Reusable checkbox component

function Checkbox({ children, disabled }) {}

const id = useId();

return (

<input id=<span className="text-green-600">{id}</span> type="checkbox" />

{children}

</label>

</div>

);

}

// Safe to use multiple times!

<Checkbox>Option 1</Checkbox>

<Checkbox>Option 2</Checkbox>

No ID Conflicts!

Each Checkbox instance gets its own unique ID, preventing conflicts and ensuring proper accessibility.

Step 5: Best Practices

Follow these guidelines to use useId effectively and avoid common pitfalls.

//DO: Use for accessibility

const id = useId();

<label htmlFor=<span className="text-green-600">{id}</span>>Label</label>

//DON'T: Use for CSS selectors

<div id=<span className="text-green-600">{id}</span> className="my-component">

//DO: Use in component libraries

function CustomInput() {}

const id = useId();

//DON'T: Use for list keys

items.map(item => (

<div key=<span className="text-green-600">{useId()}</span>> // Wrong!

))

Golden Rule

Use useId only for connecting HTML elements. For list keys, use stable identifiers from your data.

Example: Accessible Form Component

Building a complete accessible form with useId

Accessible Form with useId

Complete form with proper accessibility connections

Frontend

function FormField({ label, type = 'text', error, required = false }) {
  const id = useId();
  const errorId = useId();

  return (
    <div className="form-field">
      <label htmlFor={id}>
        {label}
        {required && <span className="required">*</span>}
      </label>
      <input
        id={id}
        type={type}
        aria-describedby={error ? errorId : undefined}
        aria-invalid={error ? 'true' : 'false'}
        required={required}
      />
      {error && (
        <div id={errorId} className="error-message" role="alert">
          {error}
        </div>
      )}
    </div>
  );
}

function SignUpForm() {
  const [formData, setFormData] = React.useState({
    name: '',
    email: '',
    password: ''
  });
  const [errors, setErrors] = React.useState({});

  const validateForm = () => {
    const newErrors = {};
    
    if (!formData.name.trim()) {
      newErrors.name = 'Name is required';
    }
    
    if (!formData.email.trim()) {
      newErrors.email = 'Email is required';
    } else if (!/\S+@\S+\.\S+/.test(formData.email)) {
      newErrors.email = 'Email is invalid';
    }
    
    if (!formData.password) {
      newErrors.password = 'Password is required';
    } else if (formData.password.length < 8) {
      newErrors.password = 'Password must be at least 8 characters';
    }
    
    setErrors(newErrors);
    return Object.keys(newErrors).length === 0;
  };

  const handleSubmit = (e) => {
    e.preventDefault();
    if (validateForm()) {
      alert('Form submitted successfully!');
      setFormData({ name: '', email: '', password: '' });
      setErrors({});
    }
  };

  const handleChange = (field) => (e) => {
    setFormData(prev => ({ ...prev, [field]: e.target.value }));
    // Clear error when user starts typing
    if (errors[field]) {
      setErrors(prev => ({ ...prev, [field]: '' }));
    }
  };

  return (
    <div className="container">
      <div className="form-header">
        <h1>🔐 Create Account</h1>
        <p>Join us today! All fields are required.</p>
      </div>

      <form onSubmit={handleSubmit} className="signup-form">
        <FormField
          label="Full Name"
          value={formData.name}
          onChange={handleChange('name')}
          error={errors.name}
          required
        />
        
        <FormField
          label="Email Address"
          type="email"
          value={formData.email}
          onChange={handleChange('email')}
          error={errors.email}
          required
        />
        
        <FormField
          label="Password"
          type="password"
          value={formData.password}
          onChange={handleChange('password')}
          error={errors.password}
          required
        />

        <div className="form-actions">
          <button type="submit" className="submit-btn">
            Sign Up
          </button>
        </div>
      </form>

      <div className="accessibility-info">
        <h2>♿ Accessibility Features</h2>
        <ul>
          <li>✅ All form fields have proper label connections</li>
          <li>✅ Error messages are announced by screen readers</li>
          <li>✅ Required fields are clearly marked</li>
          <li>✅ Form validation provides helpful feedback</li>
          <li>✅ Unique IDs prevent conflicts</li>
        </ul>
      </div>
    </div>
  );
}

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(<SignUpForm />);

Live Preview

Loading preview...

Key Concepts

Understanding useId fundamentals

Unique Generation

Each useId() call generates a unique identifier that won't conflict with other IDs.

SSR Compatible

IDs are stable across server and client rendering, preventing hydration mismatches.

Performance

Lightweight and fast - no performance overhead compared to manual ID generation.

Best Practices

Do's and Don'ts for useId

✅ Do This

Use for form label connections
Use with ARIA attributes
Create reusable components
Use in component libraries

❌ Avoid This

Don't use for CSS selectors
Don't use for list keys
Don't use for data attributes
Don't rely on ID format

Accessibility First!

useId is your best friend for building accessible React components. Always use it for connecting HTML elements!

Coder Pod - Learn Programming Online | AI Coding Tutor & Interview Practice

useDebugValue Hook

useSyncExternalStore

Building Your Learning Module...

useId Hook

Basic Syntax

Server-Side Safe

Accessibility Focus

SSR Compatible!

Form Accessibility

ARIA Attributes

Component Libraries

💡 Pro Tip

Step 1: Generate an ID

Step 2: Connect Form Elements

Step 3: Use with ARIA Attributes

Step 4: Create Reusable Components

Step 5: Best Practices

Accessible Form with useId

Unique Generation

SSR Compatible

Performance

✅ Do This

❌ Avoid This

Accessibility First!

useDebugValue Hook

useSyncExternalStore

useId Hook

Basic Syntax

Server-Side Safe

Accessibility Focus

SSR Compatible!

Form Accessibility

ARIA Attributes

Component Libraries

💡 Pro Tip

Step 1: Generate an ID

Step 2: Connect Form Elements

Step 3: Use with ARIA Attributes

Step 4: Create Reusable Components

Step 5: Best Practices

Accessible Form with useId

Unique Generation

SSR Compatible

Performance

✅ Do This

❌ Avoid This

Accessibility First!