README
useFocusTrap
Trap keyboard focus inside a DOM element, to prevent the user navigating outside a modal.
When using this, make sure to combine it with a fixed position <Backdrop>
that prevents the mouse from clicking input elements.
Checkout the Storybook demo.
Installation
yarn add @charlietango/use-focus-trap
API
const ref = useFocusTrap(active, options)
The useFocusTrap
hook returns a ref
that you should assign to the DOM element that needs to trap focus.
Anything outside that element, will no longer be able to receive focus.
You can toggle the trap by setting the active
boolean. By default it's activated once the ref
is assigned.
Options
The focus trap accepts an object with these optional options, that give you a bit more control.
Name | Type | Default | Required | Description |
---|---|---|---|---|
focusSelector | string / HTMLElement |
undefined |
false | Assign focus when activated to the element matching this selector - or a specific element you supply. By default focus will be set to the first valid tab target. |
disableAriaHider | boolean |
false |
false | Disables setting aria-hidden on other elements inside the document.body while the trap is active. |
Example
import React from 'react'
import useFocusTrap from '@charlietango/use-focus-trap'
const Component = () => {
const ref = useFocusTrap()
return (
<div ref={ref}>
<button>Trapped to the button</button>
</div>
)
}
export default Component
Creating a Modal
When using this hook to create a Modal, there are still a few things you need to handle, that's outside the scope of this hook:
- Trap focus
- Close on escape
- Close on backdrop clicked
BaseModal.tsx
This is the base component for creating a <Modal />
. It receives an onRequestClose
method,
that can be triggered to tell the containing component to update it's state to close the modal.
It doesn't contain a <Backdrop />
, but that would be a absolute positioned component, that
when clicked triggers the onRequestClose
method.
import React, { useEffect } from 'react'
import ReactDOM from 'react-dom'
import useFocusTrap from '@charlietango/use-focus-trap'
import styled from 'styled-components'
type Props = {
onRequestClose?: () => void
children?: React.ReactNode
isOpen: boolean
className?: string
}
const Wrapper = styled.div`
position: fixed;
left: 0;
right: 0;
top: 0;
bottom: 0;
z-index: 5;
`
function BaseModal({ children, isOpen, onRequestClose, className }: Props) {
const ref = useFocusTrap()
function handleKeyDown(event: KeyboardEvent) {
if (event.key === 'Escape') {
if (onRequestClose) onRequestClose()
}
}
useEffect(() => {
if (isOpen) {
document.addEventListener('keydown', handleKeyDown)
return () => {
document.removeEventListener('keydown', handleKeyDown)
}
}
return
}, [isOpen])
const modal = (
<Wrapper
ref={ref}
style={{ pointerEvents: !isOpen ? 'none' : undefined }}
role="dialog"
className={className}
>
{children}
</Wrapper>
)
return ReactDOM.createPortal(modal, window.document.body)
}
BaseModal.displayName = 'BaseModal'
BaseModal.defaultProps = {}
export default BaseModal