platform/packages/ui/src/resize.ts
Andrey Sobolev b2435326fd
UBER-963: Related issues (#3773)
Signed-off-by: Andrey Sobolev <haiodo@gmail.com>
2023-10-03 01:20:37 +07:00

59 lines
1.7 KiB
TypeScript

// Copyright © 2022 Hardcore Engineering Inc.
//
// Licensed under the Eclipse Public 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 https://www.eclipse.org/legal/epl-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
import { DelayedCaller } from './utils'
// limitations under the License.
let observer: ResizeObserver
let callbacks: WeakMap<Element, (element: Element) => any>
const delayedCaller = new DelayedCaller(10)
/**
* @public
*/
export function resizeObserver (element: Element, onResize: (element: Element) => any): { destroy: () => void } {
if (observer === undefined) {
callbacks = new WeakMap()
const entriesPending = new Set<Element>()
const notifyObservers = (): void => {
window.requestAnimationFrame(() => {
for (const target of entriesPending.values()) {
const onResize = callbacks.get(target)
if (onResize != null) {
onResize(target)
}
}
entriesPending.clear()
})
}
observer = new ResizeObserver((entries) => {
for (const entry of entries) {
entriesPending.add(entry.target)
}
delayedCaller.call(notifyObservers)
})
}
callbacks.set(element, onResize)
observer.observe(element)
return {
destroy: () => {
callbacks.delete(element)
observer.unobserve(element)
}
}
}