56 lines
2.2 KiB
JavaScript
56 lines
2.2 KiB
JavaScript
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/**
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* @license
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* Copyright 2019 Google Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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/**
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* Determine whether the current browser supports passive event listeners, and
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* if so, use them.
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*/
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export function applyPassive(globalObj) {
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if (globalObj === void 0) { globalObj = window; }
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return supportsPassiveOption(globalObj) ?
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{ passive: true } :
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false;
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}
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function supportsPassiveOption(globalObj) {
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if (globalObj === void 0) { globalObj = window; }
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// See
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// https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener
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var passiveSupported = false;
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try {
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var options = {
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// This function will be called when the browser
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// attempts to access the passive property.
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get passive() {
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passiveSupported = true;
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return false;
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}
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};
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var handler = function () { };
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globalObj.document.addEventListener('test', handler, options);
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globalObj.document.removeEventListener('test', handler, options);
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}
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catch (err) {
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passiveSupported = false;
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}
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return passiveSupported;
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}
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//# sourceMappingURL=events.js.map
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