material-motion
Version:
Makes it easy to add rich, interactive motion to your application.
47 lines • 2.01 kB
JavaScript
/** @license
* Copyright 2016 - present The Material Motion Authors. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy
* of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
import { MotionObservable, } from '../observables/MotionObservable';
// Passive event feature detection from
// https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md
let supportsPassiveListeners = false;
try {
const eventOptions = Object.defineProperty({}, 'passive', {
get() {
supportsPassiveListeners = true;
}
});
window.addEventListener("test", () => { }, eventOptions);
}
catch (e) { }
export function getEventStreamFromElement(type, element, eventListenerOptions = { passive: true }) {
return new MotionObservable((observer) => {
if (!supportsPassiveListeners) {
eventListenerOptions = (eventListenerOptions.capture || false);
}
const next = observer.next.bind(observer);
// For some reason, TypeScript has an interface for
// AddEventListenerOptions, but its addEventListener signature hasn't been
// updated to use it, so for now, we manually cast to boolean.
//
// https://github.com/Microsoft/TypeScript/issues/18136
element.addEventListener(type, next, eventListenerOptions);
return () => {
element.removeEventListener(type, next, eventListenerOptions);
};
});
}
export default getEventStreamFromElement;
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