README
arrow-key-navigation
Overview
arrow-key-navigation
is a simple utility to add left/right focus navigation to a web app. It's
designed for KaiOS apps but also available for any browser.
The basic idea is to make the ← and → keys act similar to Tab and Shift+Tab, i.e. to change focus between focusable elements in the DOM. Since the ↑ and ↓ keys typically scroll the page in KaiOS, this is usually all you need to add basic KaiOS accessibility to an existing web app.
It will also listen for the Enter key for certain special cases like checkbox/radio buttons. contenteditable
and Shadow DOM are also supported.
Install
npm install --save arrow-key-navigation
Or browse unpkg.com for a list of build files.
Usage
import * as arrowKeyNavigation from 'arrow-key-navigation'
arrowKeyNavigation.register() // start listening for key inputs
arrowKeyNavigation.unregister() // stop listening
Focus traps
To build an accessible dialog, you need to "trap" focus inside of the dialog, i.e. make it so focus cannot escape the dialog while it is active. To accomplish this, you can set a "focus trap test" which takes an element as input and returns truthy/falsy to indicate that the element is a focus trap (e.g. the modal dialog root):
arrowKeyNavigation.setFocusTrapTest(element => {
return element.classList.contains('my-dialog-class')
})
If you don't call setFocusTrapTest()
, then arrow-key-navigation
will assume that there are no focus traps
in your app.
Conditional or lazy loading
You can choose to install this module only in KaiOS environments using logic like the following:
if (/KAIOS/.test(navigator.userAgent)) {
import('arrow-key-navigation').then(arrowKeyNavigation => {
arrowKeyNavigation.register()
})
}
Contributing
Build
npm run build
Lint
npm run lint
Fix most lint issues
npm run lint:fix
Test
npm test
Code coverage
npm run cover
Manual KaiOS app test
The index.html
and manifest.webapp
files are designed for a quick-and-dirty KaiOS app test.
Run npm run build
and then install the root directory as a packaged KaiOS app to test it.