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41 lines
1.5 KiB
41 lines
1.5 KiB
/* |
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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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/** |
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* Takes a performance entry type and a callback function, and creates a |
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* `PerformanceObserver` instance that will observe the specified entry type |
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* with buffering enabled and call the callback _for each entry_. |
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* |
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* This function also feature-detects entry support and wraps the logic in a |
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* try/catch to avoid errors in unsupporting browsers. |
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*/ |
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export const observe = (type, callback) => { |
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try { |
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if (PerformanceObserver.supportedEntryTypes.includes(type)) { |
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// More extensive feature detect needed for Firefox due to: |
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// https://github.com/GoogleChrome/web-vitals/issues/142 |
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if (type === 'first-input' && !('PerformanceEventTiming' in self)) { |
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return; |
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} |
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const po = new PerformanceObserver((l) => l.getEntries().map(callback)); |
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po.observe({ type, buffered: true }); |
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return po; |
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} |
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} |
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catch (e) { |
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// Do nothing. |
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} |
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return; |
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};
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