Simple function to make your overlays element accessible

accessible-overlays.js

// forked by a script of https://github.com/nilssolanki
import { add } from 'bianco.events'

/**
 * A list of all the open overlays, tooltips, sidebars etc.
 * @type {Map}
 */
const openOverlays = new Map()

/**
 * Add an opened overlay to the queue
 * @param {*} key – Any kind of js instance
 * @param {Function} closerFn – A function to allow closing the overlay
 * @returns {Map} - the overlays map
 */
export function subscribe(key, closerFn) {
  openOverlays.set(key, closerFn)
  return openOverlays
}

/**
 * @param {*} key – The instance used to register the overlay close function
 * @returns {Boolean} true if the overlay was correctly unsubscribed
 */
export function unsubscribe(key) {
  const found = openOverlays.has(key)
  if (found) openOverlays.delete(key)
  return found
}

const ESC_KEY = 27

/**
 * If the esc key is pressed, close the last overlay added to the list
 */
add(document, 'keyup', ({ keyCode }) => {
  if (keyCode === ESC_KEY && openOverlays.size) {
    const [, closerFn] = Array.from(openOverlays).pop()
    closerFn()
  }
})