64 lines
2.1 KiB
JavaScript
64 lines
2.1 KiB
JavaScript
import { bindReporter } from './lib/bindReporter.js';
|
|
import { getVisibilityWatcher } from './lib/getVisibilityWatcher.js';
|
|
import { initMetric } from './lib/initMetric.js';
|
|
import { observe } from './lib/observe.js';
|
|
import { onHidden } from './lib/onHidden.js';
|
|
|
|
/*
|
|
* Copyright 2020 Google LLC
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* https://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
/**
|
|
* Calculates the [FID](https://web.dev/fid/) value for the current page and
|
|
* calls the `callback` function once the value is ready, along with the
|
|
* relevant `first-input` performance entry used to determine the value. The
|
|
* reported value is a `DOMHighResTimeStamp`.
|
|
*
|
|
* _**Important:** since FID is only reported after the user interacts with the
|
|
* page, it's possible that it will not be reported for some page loads._
|
|
*/
|
|
const onFID = (onReport) => {
|
|
const visibilityWatcher = getVisibilityWatcher();
|
|
const metric = initMetric('FID');
|
|
// eslint-disable-next-line prefer-const
|
|
let report;
|
|
|
|
const handleEntry = (entry) => {
|
|
// Only report if the page wasn't hidden prior to the first input.
|
|
if (entry.startTime < visibilityWatcher.firstHiddenTime) {
|
|
metric.value = entry.processingStart - entry.startTime;
|
|
metric.entries.push(entry);
|
|
report(true);
|
|
}
|
|
};
|
|
|
|
const handleEntries = (entries) => {
|
|
(entries ).forEach(handleEntry);
|
|
};
|
|
|
|
const po = observe('first-input', handleEntries);
|
|
report = bindReporter(onReport, metric);
|
|
|
|
if (po) {
|
|
onHidden(() => {
|
|
handleEntries(po.takeRecords() );
|
|
po.disconnect();
|
|
}, true);
|
|
}
|
|
};
|
|
|
|
export { onFID };
|
|
//# sourceMappingURL=getFID.js.map
|