react-focus-lock

What is react-focus-lock?

The react-focus-lock package is a React component designed to trap focus within a DOM element. It is commonly used to ensure that keyboard users can navigate modal dialogs and other pop-up UI elements without accidentally interacting with the rest of the page.

What are react-focus-lock's main functionalities?

Focus Trapping

This feature traps the focus within the modal dialog. When the modal is open, the focus cycles through the interactive elements inside the modal and does not move to the background elements.

{"import React from 'react';\nimport FocusLock from 'react-focus-lock';\n\nconst Modal = ({ onClose }) => (\n  <FocusLock>\n    <div className='modal'>\n      <button onClick={onClose}>Close</button>\n      {/* other modal contents */}\n    </div>\n  </FocusLock>\n);"}

AutoFocus and Return Focus

This feature automatically focuses the first focusable element within the FocusLock on mount and returns the focus to the initially focused element when the FocusLock is unmounted.

{"import React from 'react';\nimport FocusLock from 'react-focus-lock';\n\nconst Modal = ({ onClose }) => (\n  <FocusLock autoFocus={true} returnFocus={true}>\n    <div className='modal'>\n      <button onClick={onClose}>Close</button>\n      {/* other modal contents */}\n    </div>\n  </FocusLock>\n);"}

Focus Grouping

This feature allows grouping of focusable elements. Focus can be moved inside a group, and it will be contained within the elements of that group.

{"import React from 'react';\nimport FocusLock, { MoveFocusInside } from 'react-focus-lock';\n\nconst Group = () => (\n  <div>\n    <MoveFocusInside>\n      <button>Button1</button>\n    </MoveFocusInside>\n    <MoveFocusInside>\n      <button>Button2</button>\n    </MoveFocusInside>\n  </div>\n);\n\nconst App = () => (\n  <FocusLock group='group1'>\n    <Group />\n  </FocusLock>\n);"}

Other packages similar to react-focus-lock

react-modal

react-modal is a package that provides accessible modals for React applications. It includes the ability to trap focus within the modal, similar to react-focus-lock, but it is specifically designed for modal dialog creation and management.

react-aria-modal

react-aria-modal is a fully accessible React modal component that manages focus. It also traps focus within the modal, similar to react-focus-lock, and provides a comprehensive solution for creating accessible modals with ARIA attributes.

react-trap-focus

react-trap-focus is a package that provides focus trapping functionality. It is similar to react-focus-lock in that it traps focus within a specified element, but it may have different implementation details or additional features.

README

react-focus-lock

It is a trap! We got your focus and will not let him out!

This is a small, but very useful for:

• Modal dialogs. You can not leave it with "Tab", ie tab-out.
• Focused tasks. It will aways brings you back.

You have to use it in every modal dialog, or you a11y will be shitty.

How to use

Just wrap something with focus lock, and focus will be moved inside on mount.

 import FocusLock from 'react-focus-lock';

 const JailForAFocus = ({onClose}) => (
    <FocusLock>
      You can not leave this form
      <button onClick={onClick} />
    </FocusLock>
 );

Demo - https://codesandbox.io/s/72prk69z3j

WHY?

From MDN Article about accessible dialogs:

• The dialog must be properly labeled
• Keyboard focus must be managed correctly

This one is about managing the focus.

I'v got a good article about focus management, dialogs and WAI-ARIA.

Behavior

1. It will always keep focus inside Lock.
2. It will cycle forward then you press Tab.
3. It will cycle in reverse direction on Shift+Tab.
4. It will do it using browser tools, not emulation.
5. It will handle positive tabIndex inside form.
6. It will prevent any jump outside, returning focus to the last element.

You can use nested Locks or have more than one Lock on the page. Only last, or deepest one will work. No fighting.

API

FocusLock has few props to tune behavior

• disabled, to disable(enable) behavior without altering the tree.
• returnFocus, to return focus into initial position on unmount(not disable). This is expected behavior for Modals, but it is better to implement it by your self.
• allowTextSelection enabled text selections inside, and outside focus lock.
• noFocusGuards disabled focus guards - virtual inputs which secure tab index.

Autofocus

As long you cannot use autoFocus prop - cos "focusing" should be delayed to Trap activation, and autoFocus will effect immediately - Focus Lock provide a special API for it

• prop data-autofocus on the element.
• AutoFocusInside component, as named export of this library.

 import FocusLock, { AutoFocusInside } from 'focus-lock';
 <FocusLock>
   <button>Click</button>
   <AutoFocusInside>
    <button>will be focused</button>
   </AutoFocusInside>
 </FocusLock>
 // is the same as
 <FocusLock>
   <button>Click</button>
    <button data-autofocus>will be focused</button>
 </FocusLock>

If there is more than one auto-focusable target - the first will be selected. If it is a part of radio group, and rest of radio group element are also autofocusable(just put them into AutoFocusInside) - checked one fill be selected.

Unmounting and focus management

• In case FocusLock has returnFocus enabled, and it's gonna to be unmounted - focus will be returned after zero-timeout.
• In case returnFocus did not set, and you are going to control focus change by your own - keep in mind

React will first call Parent.componentWillUnmount, and next Child.componentWillUnmount

Thus means - Trap will be still active, be the time you may want move(return) focus on componentWillUnmount. Please deffer this action with a zero-timeout.

How it works

Everything thing is simple - react-focus-lock just dont left focus left boundaries of component, and do something only if escape attempt was succeeded.

It is not altering tabbing behavior at all. We are good citizens.

Not only for React

Uses focus-lock under the hood. It does also provide support for Vue.js and Vanilla DOM solutions

Licence

MIT