39 lines
1.2 KiB
TypeScript
39 lines
1.2 KiB
TypeScript
/*
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* Copyright 2024 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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import {onHidden} from './onHidden.js';
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import {runOnce} from './runOnce.js';
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/**
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* Runs the passed callback during the next idle period, or immediately
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* if the browser's visibility state is (or becomes) hidden.
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*/
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export const whenIdle = (cb: () => void): number => {
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const rIC = self.requestIdleCallback || self.setTimeout;
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let handle = -1;
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cb = runOnce(cb);
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// If the document is hidden, run the callback immediately, otherwise
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// race an idle callback with the next `visibilitychange` event.
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if (document.visibilityState === 'hidden') {
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cb();
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} else {
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handle = rIC(cb);
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onHidden(cb);
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}
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return handle;
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};
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