33 lines
1.4 KiB
JavaScript
33 lines
1.4 KiB
JavaScript
/*
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* Copyright 2022 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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export const getNavigationEntry = () => {
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const navigationEntry = self.performance &&
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performance.getEntriesByType &&
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performance.getEntriesByType('navigation')[0];
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// Check to ensure the `responseStart` property is present and valid.
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// In some cases no value is reported by the browser (for
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// privacy/security reasons), and in other cases (bugs) the value is
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// negative or is larger than the current page time. Ignore these cases:
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// https://github.com/GoogleChrome/web-vitals/issues/137
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// https://github.com/GoogleChrome/web-vitals/issues/162
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// https://github.com/GoogleChrome/web-vitals/issues/275
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if (navigationEntry &&
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navigationEntry.responseStart > 0 &&
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navigationEntry.responseStart < performance.now()) {
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return navigationEntry;
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}
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};
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