Pinafore-Web-Client-Frontend/routes/_utils/delegate.js

50 lines
1.3 KiB
JavaScript

// Delegate certain events to the global document for perf purposes.
import { mark, stop } from './marks'
const callbacks = {}
if (process.browser && process.env.NODE_ENV !== 'production') {
window.delegateCallbacks = callbacks
}
function onEvent(e) {
let { type, keyCode, target } = e
if (!(type === 'click' || (type === 'keydown' && keyCode === 13))) {
// we're not interested in any non-click or non-Enter events
return
}
mark('delegate onEvent')
let attr = `delegate-${type}-key`
let key
let element = target
while (element) {
if ((key = element.getAttribute(attr))) {
break
}
element = element.parentElement
}
if (key && callbacks[type] && callbacks[type][key]) {
callbacks[type][key](e)
}
stop('delegate onEvent')
}
export function registerDelegate(type, key, callback) {
mark('delegate registerDelegate')
callbacks[type] = callbacks[type] || {}
callbacks[type][key] = callback
stop('delegate registerDelegate')
}
export function unregisterDelegate(type, key) {
mark('delegate unregisterDelegate')
callbacks[type] = callbacks[type] || {}
delete callbacks[type][key]
stop('delegate unregisterDelegate')
}
if (process.browser) {
document.addEventListener('click', onEvent)
document.addEventListener('keydown', onEvent)
}