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

• browser friendly focus lock
  
• matching all your use cases
  
• trusted by best UI frameworks
  
• the thing Admiral Ackbar was talking about
  
  

---

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

• Modal dialogs. You can not leave it with "Tab", ie do a "tab-out".
• Focused tasks. It will aways brings you back, as you can "lock" user inside a component.
• Any any other case, when you have to lock user intention and focus, if that's what a11y is asking for.

Trusted

Trusted by Atlassian AtlasKit, ReachUI, SmoothUI, Storybook and we will do our best to earn your trust too!

Features

• no keyboard control, everything is done watching a focus behavior, not emulating it. Thus works always and everywhere.
• React Portals support. Even if some data is in outer space - it is still in lock.
• Scattered locks, or focus lock groups - you can setup different isolated locks, and tab from one to another.
• Controllable isolation level.
• variable size bundle. Uses sidecar to trim UI part to 1.5kb.

💡 focus locks is only the first part, there are also scroll lock and text-to-speech lock you have to use to really "lock" the user. Try react-focus-on to archive everything above, assembled in the right order.

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={onClose} />
    </FocusLock>
 );

Demo - https://codesandbox.io/s/5wmrwlvxv4.

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

API

FocusLock would work perfectly even with no props set.

FocusLock has few props to tune behavior, all props are optional:

• disabled, to disable(enable) behavior without altering the tree.
• className, to set the className of the internal wrapper.
• returnFocus, to return focus into initial position on unmount(not disable).

By default returnFocus is disabled, so FocusLock will not restore original focus on deactivation.

This is expected behavior for Modals, but it is better to implement it by your self. See unmounting and focus management for details

• persistentFocus=false, requires any element to be focused. This also disables text selections inside, and outside focus lock.
• autoFocus=true, enables or disables focusing into on Lock activation. If disabled Lock will blur an active focus.
• noFocusGuards=false disabled focus guards - virtual inputs which secure tab index.
• group=''' named focus group for focus scattering aka combined lock targets
• shards=[] an array of ref pointing to the nodes, which focus lock should consider and a part of it. This is another way focus scattering.
• whiteList=fn you could whitelist locations FocusLock should carry about. Everything outside it will ignore. For example - any modals.
• as='div' if you need to change internal div element, to any other. Use ref forwarding to give FocusLock the node to work with.
• lockProps={} to pass any extra props (except className) to the internal wrapper.
• hasPositiveIndices=false to support a focus lock behavior when any elements tabIndex greater than 0.
• crossFrame=true enables aggressive focus capturing within iframes

Focusing in OSX (Safari/Firefox) is strange!

By default tabbing in OSX sees only controls, but not links or anything else tabbable. This is system settings, and Safari/Firefox obey. Press Option+Tab in Safari to loop across all tabbables, or change the Safari settings. There is no way to fix Firefox, unless change system settings (Control+F7). See this issue for more information.

Set up

Requirements

• version 1x is React 15/16 compatible
• version 2+ requires React 16.8+ (hooks)

Import

react-focus-lock exposed 3 entry points: for the classical usage, and a sidecar one.

Default usage

• 4kb, import FocusLock from 'react-focus-lock would give you component you are looking for.

Separated usage

Meanwhile - you dont need any focus related logic until it's needed. Thus - you may defer that logic till Lock activation and move all related code to a sidecar.

• UI, 1.5kb, import FocusLockUI from 'react-focus-lock/UI - a DOM part of a lock.
• Sidecar, 3.5kb, import Sidecar from 'react-focus-lock/sidecar - which is the real focus lock.

import FocusLockUI from "react-focus-lock/UI";
import {sidecar} from "use-sidecar";

// prefetch sidecar. data would be loaded, but js would not be executed
const FocusLockSidecar = sidecar(  
  () => import(/* webpackPrefetch: true */ "react-focus-lock/sidecar")
);

<FocusLockUI
    disabled={this.state.disabled}
    sideCar={FocusLockSidecar}
>
 {content}
</FocusLockUI> 

That would split FocusLock into two pieces, reducing app size and improving the first load. The cost of focus-lock is just 1.5kb!

Saved 3.5kb?! 🤷‍♂️ 3.5kb here and 3.5kb here, and your 20mb bundle is ready.

Autofocus

Use when you cannot use the native autoFocus prop - because you only want to autofocus once the Trap has been activated

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

 import FocusLock, { AutoFocusInside } from 'react-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.

AutoFocusInside will work only on Lock activation, and does nothing, then used outside of the lock. You can use MoveFocusInside to move focus inside with or without lock.

 import { MoveFocusInside } from 'react-focus-lock';
    
 <MoveFocusInside>
  <button>will be focused</button>
 </MoveFocusInside>

Portals

Use focus scattering to handle portals

• using groups. Just create a few locks (only one could be active) with a same group name

const PortaledElement = () => (
   <FocusLock group="group42" disabled={true}>
     // "discoverable" portaled content
   </FocusLock>  
);

<FocusLock group="group42">
  // main content
</FocusLock>

• using shards. Just pass all the pieces to the "shards" prop.

const PortaledElement = () => (
   <div ref={ref}>
     // "discoverable" portaled content
   </div>  
);

<FocusLock shards={[ref]}>
  // main content
</FocusLock>

• without anything. FocusLock will not prevent focusing portaled element, but will not include them in to tab order

const PortaledElement = () => (
   <div>
     // NON-"discoverable" portaled content
   </div>  
);

<FocusLock shards={[ref]}>
  // main content
  <PortaledElement />
</FocusLock>

Using your own Components

You may use as prop to change what Focus-Lock will render around children.

<FocusLock as="section">
    <button>Click</button>
    <button data-autofocus>will be focused</button>
 </FocusLock>
 
 <FocusLock as={AnotherComponent} lockProps={{anyAnotherComponentProp: 4}}>
    <button>Click</button>
    <span>Hello there!</span>
 </FocusLock>

Guarding

As you may know - FocusLock is adding Focus Guards before and after lock to remove some side effects, like page scrolling. But shards will not have such guards, and it might be not so cool to use them - for example if no tabbable would be defined after shard - you will tab to the browser chrome.

You may wrap shard with InFocusGuard or just drop InFocusGuard here and there - that would solve the problem.

import {InFocusGuard} from 'react-focus-lock';

// wrap with
<InFocusGuard>
  <button />
</InFocusGuard>

// place before and after
<InFocusGuard />
<button />
<InFocusGuard />

InFocusGuards would be active(tabbable) only when tabble, it protecting, is focused.

Removing Tailing Guard

If only your modal is the last tabble element on the body - you might remove the Tailing Guard, to allow user tab into address bar.

<InFocusGuard/>
<button />  
// there is no "tailing" guard :)

Unmounting and focus management

• In case FocusLock has returnFocus enabled, and it's going to be unmounted - focus will be returned after zero-timeout.
• In case returnFocus is set to false, and you are going to control focus change on your own - keep in mind

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

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

Similarly, if you are using the disabled prop to control FocusLock, you will need a zero-timeout to correctly restore focus.

<FocusLock
  disabled={isFocusLockDisabled}
  onDeactivation={() => {
    // Without the zero-timeout, focus will likely remain on the button/control
    // you used to set isFocusLockDisabled = true
    window.setTimeout(() => myRef.current.focus(), 0);
  }
>

Return focus with no scroll

read more at the issue #83 or mdn article.

To return focus, but without jumpy page scroll returning a focus you might specify a focus option

<FocusLock
  returnFocus={{ preventScroll: false }} // working not in all browsers
>   

Not supported by Edge and Safari.

Not only for React

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

Warning!

Two different focus-lock-managers or even different version of a single one, active simultaneously will FIGHT!

Focus-lock will surrender, as long any other focus management library will not.

Focus fighting

You may wrap some render branch with FreeFocusInside, and react-focus-lock will ignore any focus inside marked node, thus landing a peace.

import { FreeFocusInside } from 'react-focus-lock';

<FreeFocusInside>
 <div id="portal-for-modals">
   in this div i am going to portal my modals, dont fight with them please
 </div>
</FreeFocusInside>

Even the better is to whiteList FocusLock areas - for example "you should handle only React Stuff in React Root"

<FocusLock whiteList={node => document.getElementById('root').contains(node)}>
 ...
</FocusLock>

PS: please use webpack or yarn resolution for force one version of react-focus-lock used

webpack.conf

 resolve: {    
    alias: {
      'react-focus-lock': path.resolve(path.join(__dirname, './node_modules/react-focus-lock'))
 ...

More

To create a "right" modal dialog you have to:

• manage a focus. Use this library
• block document scroll. Use react-scroll-locky.
• hide everything else from screen readers. Use aria-hidden

You may use react-focus-on to achieve everything above, assembled in the right order.

Licence

MIT