/* * 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. */ 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 { onBFCacheRestore } from './lib/onBFCacheRestore.js'; import { onHidden } from './lib/onHidden.js'; import { firstInputPolyfill, resetFirstInputPolyfill } from './lib/polyfills/firstInputPolyfill.js'; export const getFID = (onReport, reportAllChanges) => { const visibilityWatcher = getVisibilityWatcher(); let metric = initMetric('FID'); let report; const entryHandler = (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 po = observe('first-input', entryHandler); report = bindReporter(onReport, metric, reportAllChanges); if (po) { onHidden(() => { po.takeRecords().map(entryHandler); po.disconnect(); }, true); } if (window.__WEB_VITALS_POLYFILL__) { // Prefer the native implementation if available, if (!po) { window.webVitals.firstInputPolyfill(entryHandler); } onBFCacheRestore(() => { metric = initMetric('FID'); report = bindReporter(onReport, metric, reportAllChanges); window.webVitals.resetFirstInputPolyfill(); window.webVitals.firstInputPolyfill(entryHandler); }); } else { // Only monitor bfcache restores if the browser supports FID natively. if (po) { onBFCacheRestore(() => { metric = initMetric('FID'); report = bindReporter(onReport, metric, reportAllChanges); resetFirstInputPolyfill(); firstInputPolyfill(entryHandler); }); } } };