@yoo-digital/focus-overlay NPM

Focus Overlay

Library for creating overlays on focused elements. It was built with accessibility in mind with trigger keys and ARIA roles.

This is a fork of the original library focus-overlay. We rewrote the library to TypeScript and Sass. Furthermore we introduced the following options:

debounceScroll
debounceResize
debounceMs
watchAnimationEnd
data-focus-offset

Focus Overlay

Install

Install with npm:

npm install @yoo-digital/focus-overlay

import styles

The CSS is small enough to copy directly into your project's main stylesheet if you desire.

CSS

import "~@yoo-digital/focus-overlay/dist/focusoverlay.css"

SCSS

If you want to adjust the styling of the focus overlay, import the SCSS file instead of the CSS file and override the SCSS variables as you wish.

import "~@yoo-digital/focus-overlay/src/styles.scss"

Usage

FocusOverlay(element, options)

import FocusOverlay from 'focus-overlay';

// Option 1: Zero config - Scopes to <body> element and uses default settings
const fo = new FocusOverlay();

// Option 2: Define an element
const fo = new FocusOverlay(document.body, options);

The element is what FocusOverlay will be scoped to. It takes either a string CSS selector or an HTML element. If no element is supplied it will scope to the <body> element by default.

The options is an optional parameter. Takes an object. See options for more info.

By default Focus Overlay will show and animate when hitting keyboard keys such as the Tab key. It's also preconfigured to animate via CSS transitions.

Options

The default options are:

// Class added to the focus box
class: 'focus-overlay',
// Class added while the focus box is active
activeClass: 'focus-overlay-active',
// Class added while the focus box is animating
animatingClass: 'focus-overlay-animating',
// Class added to the target element
targetClass: 'focus-overlay-target',
// z-index of focus box
zIndex: 9001,
// Duration of the animatingClass (milliseconds)
duration: 500,
// Removes activeClass after duration
inActiveAfterDuration: false,
// Tab, Page up, Page down, End, Home, Arrow Keys, Enter, Space, Shift, Ctrl, Alt, ESC
triggerKeys: [9, 33, 34, 35, 36, 37, 38, 39, 40, 13, 32, 16, 17, 18, 27],
// Make focus box inactive when a non specified key is pressed
inactiveOnNonTriggerKey: false,
// Make focus box inactive when a user clicks
inactiveOnClick: true,
// Force the box to always stay active. Overrides everything
alwaysActive: false,
// Reposition focus box on transitionEnd for focused elements
watchTransitionEnd: true,
// Reposition focus box on animationEnd based on the window object
watchAnimationEnd: true,
// Reposition focus box on scroll event (debounce: default 150ms)
debounceScroll: true,
// Reposition focus box on resize event (debounce: default 150ms)
debounceResize: true,
// Defines the waiting time for the debounce function in milliseconds.
debounceMs: 150,
// Initialization event
onInit: function(focusoverlay) {},
// Before focus box move
onBeforeMove: function(focusoverlay) {},
// After focus box move
onAfterMove: function(focusoverlay) {},
// After FocusOverlay is destroyed
onDestroy: function(focusoverlay) {}

Methods

// Example use of the "moveFocusBox" method
focusoverlay.moveFocusBox(document.querySelector('body'));

moveFocusBox

Arguments: Element

Moves the focusBox to a target element

Destroy

Arguments: None

Deconstructs the FocusOverlay instance

Data Attribute Settings

In some cases you might want FocusOverlay to ignore certain elements, or focus other elements instead. There are a few options available:

Example usage for `data-focus`:

<div id="input-wrapper">
  <input type="text" data-focus="#input-wrapper" />
</div>

In this example when the user focuses the input, FocusOverlay will instead target the wrapper. The data-focus attribute accepts a querySelector string.

Example usage for `data-focus-label`:

<label for="stylized-checkbox" class="rounded-checkbox">Click me</label>
<input
  id="stylized-checkbox"
  type="checkbox"
  class="visually-hidden"
  data-focus-label
/>

In this example when the user focuses the input, FocusOverlay will instead target its associated label.

Example usage for `data-focus-ignore`:

<a href="/info.html" data-focus-ignore>Really important information here!</a>

In this example FocusOverlay will not target this element at all.

Example usage for `data-focus-offset`:

If you want to adjust the default offset for individual elements, you can do so by defining the data-focus-offset attribute.

<a href="/info.html" data-focus-offset={0}>Click me</a>

Browser support

Focus Overlay works on all modern browsers.

If you want to support IE11 you will have to add the following two polyfills:

Notes

Special thanks to mmahandev for initially working on focus-overlay which allowed us to fork from.
Special thanks to NV as it was inspired by his Flying Focus UI concept.