plyr/src/js/utils/events.js
2018-08-01 00:56:44 +10:00

121 lines
3.8 KiB
JavaScript

// ==========================================================================
// Event utils
// ==========================================================================
import is from './is';
// Check for passive event listener support
// https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md
// https://www.youtube.com/watch?v=NPM6172J22g
const supportsPassiveListeners = (() => {
// Test via a getter in the options object to see if the passive property is accessed
let supported = false;
try {
const options = Object.defineProperty({}, 'passive', {
get() {
supported = true;
return null;
},
});
window.addEventListener('test', null, options);
window.removeEventListener('test', null, options);
} catch (e) {
// Do nothing
}
return supported;
})();
// Toggle event listener
export function toggleListener(element, event, callback, toggle = false, passive = true, capture = false) {
// Bail if no element, event, or callback
if (!element || !('addEventListener' in element) || is.empty(event) || !is.function(callback)) {
return;
}
// Allow multiple events
const events = event.split(' ');
// Build options
// Default to just the capture boolean for browsers with no passive listener support
let options = capture;
// If passive events listeners are supported
if (supportsPassiveListeners) {
options = {
// Whether the listener can be passive (i.e. default never prevented)
passive,
// Whether the listener is a capturing listener or not
capture,
};
}
// If a single node is passed, bind the event listener
events.forEach(type => {
if (this && this.eventListeners && toggle) {
// Cache event listener
this.eventListeners.push({ element, type, callback, options });
}
element[toggle ? 'addEventListener' : 'removeEventListener'](type, callback, options);
});
}
// Bind event handler
export function on(element, events = '', callback, passive = true, capture = false) {
toggleListener.call(this, element, events, callback, true, passive, capture);
}
// Unbind event handler
export function off(element, events = '', callback, passive = true, capture = false) {
toggleListener.call(this, element, events, callback, false, passive, capture);
}
// Bind once-only event handler
export function once(element, events = '', callback, passive = true, capture = false) {
function onceCallback(...args) {
off(element, events, onceCallback, passive, capture);
callback.apply(this, args);
}
toggleListener.call(this, element, events, onceCallback, true, passive, capture);
}
// Trigger event
export function triggerEvent(element, type = '', bubbles = false, detail = {}) {
// Bail if no element
if (!is.element(element) || is.empty(type)) {
return;
}
// Create and dispatch the event
const event = new CustomEvent(type, {
bubbles,
detail: Object.assign({}, detail, {
plyr: this,
}),
});
// Dispatch the event
element.dispatchEvent(event);
}
// Unbind all cached event listeners
export function unbindListeners() {
if (this && this.eventListeners) {
this.eventListeners.forEach(item => {
const { element, type, callback, options } = item;
element.removeEventListener(type, callback, options);
});
this.eventListeners = [];
}
}
// Run method when / if player is ready
export function ready() {
return new Promise(
resolve => (this.ready ? setTimeout(resolve, 0) : on.call(this, this.elements.container, 'ready', resolve)),
).then(() => {});
}