38 lines
1.3 KiB
JavaScript
38 lines
1.3 KiB
JavaScript
/*
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* Copyright 2020 Google LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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let isUnloading = false;
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let listenersAdded = false;
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const onPageHide = (event) => {
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isUnloading = !event.persisted;
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};
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const addListeners = () => {
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addEventListener('pagehide', onPageHide);
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// `beforeunload` is needed to fix this bug:
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// https://bugs.chromium.org/p/chromium/issues/detail?id=987409
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// eslint-disable-next-line @typescript-eslint/no-empty-function
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addEventListener('beforeunload', () => { });
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};
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export const onHidden = (cb, once = false) => {
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if (!listenersAdded) {
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addListeners();
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listenersAdded = true;
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}
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addEventListener('visibilitychange', ({ timeStamp }) => {
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if (document.visibilityState === 'hidden') {
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cb({ timeStamp, isUnloading });
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}
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}, { capture: true, once });
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};
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