You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 

30 lines
1.2 KiB

/*
* Copyright 2020 Google LLC
*
* 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
*
* https://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.
*/
export const onHidden = (cb, once) => {
const onHiddenOrPageHide = (event) => {
if (event.type === 'pagehide' || document.visibilityState === 'hidden') {
cb(event);
if (once) {
removeEventListener('visibilitychange', onHiddenOrPageHide, true);
removeEventListener('pagehide', onHiddenOrPageHide, true);
}
}
};
addEventListener('visibilitychange', onHiddenOrPageHide, true);
// Some browsers have buggy implementations of visibilitychange,
// so we use pagehide in addition, just to be safe.
addEventListener('pagehide', onHiddenOrPageHide, true);
};