noway.gabb.fr
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1import { bindReporter } from './lib/bindReporter.js';
2import { getVisibilityWatcher } from './lib/getVisibilityWatcher.js';
3import { initMetric } from './lib/initMetric.js';
4import { observe } from './lib/observe.js';
5import { onHidden } from './lib/onHidden.js';
6
7/*
8 * Copyright 2020 Google LLC
9 *
10 * Licensed under the Apache License, Version 2.0 (the "License");
11 * you may not use this file except in compliance with the License.
12 * You may obtain a copy of the License at
13 *
14 * https://www.apache.org/licenses/LICENSE-2.0
15 *
16 * Unless required by applicable law or agreed to in writing, software
17 * distributed under the License is distributed on an "AS IS" BASIS,
18 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 * See the License for the specific language governing permissions and
20 * limitations under the License.
21 */
22
23/**
24 * Calculates the [FID](https://web.dev/fid/) value for the current page and
25 * calls the `callback` function once the value is ready, along with the
26 * relevant `first-input` performance entry used to determine the value. The
27 * reported value is a `DOMHighResTimeStamp`.
28 *
29 * _**Important:** since FID is only reported after the user interacts with the
30 * page, it's possible that it will not be reported for some page loads._
31 */
32const onFID = (onReport) => {
33 const visibilityWatcher = getVisibilityWatcher();
34 const metric = initMetric('FID');
35 // eslint-disable-next-line prefer-const
36 let report;
37
38 const handleEntry = (entry) => {
39 // Only report if the page wasn't hidden prior to the first input.
40 if (entry.startTime < visibilityWatcher.firstHiddenTime) {
41 metric.value = entry.processingStart - entry.startTime;
42 metric.entries.push(entry);
43 report(true);
44 }
45 };
46
47 const handleEntries = (entries) => {
48 (entries ).forEach(handleEntry);
49 };
50
51 const po = observe('first-input', handleEntries);
52 report = bindReporter(onReport, metric);
53
54 if (po) {
55 onHidden(() => {
56 handleEntries(po.takeRecords() );
57 po.disconnect();
58 }, true);
59 }
60};
61
62export { onFID };
63//# sourceMappingURL=getFID.js.map