From 8eff962cab608341a6f2fedc640a0e32d96f26e2 Mon Sep 17 00:00:00 2001 From: altaf-creator Date: Sun, 9 Nov 2025 11:15:19 +0800 Subject: pain --- frontend-old/node_modules/web-vitals/src/onLCP.ts | 134 ++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 frontend-old/node_modules/web-vitals/src/onLCP.ts (limited to 'frontend-old/node_modules/web-vitals/src/onLCP.ts') diff --git a/frontend-old/node_modules/web-vitals/src/onLCP.ts b/frontend-old/node_modules/web-vitals/src/onLCP.ts new file mode 100644 index 0000000..57f0a85 --- /dev/null +++ b/frontend-old/node_modules/web-vitals/src/onLCP.ts @@ -0,0 +1,134 @@ +/* + * 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 {onBFCacheRestore} from './lib/bfcache.js'; +import {bindReporter} from './lib/bindReporter.js'; +import {doubleRAF} from './lib/doubleRAF.js'; +import {getActivationStart} from './lib/getActivationStart.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'; +import {runOnce} from './lib/runOnce.js'; +import {whenActivated} from './lib/whenActivated.js'; +import {whenIdle} from './lib/whenIdle.js'; +import {LCPMetric, MetricRatingThresholds, ReportOpts} from './types.js'; + +/** Thresholds for LCP. See https://web.dev/articles/lcp#what_is_a_good_lcp_score */ +export const LCPThresholds: MetricRatingThresholds = [2500, 4000]; + +const reportedMetricIDs: Record = {}; + +/** + * Calculates the [LCP](https://web.dev/articles/lcp) value for the current page and + * calls the `callback` function once the value is ready (along with the + * relevant `largest-contentful-paint` performance entry used to determine the + * value). The reported value is a `DOMHighResTimeStamp`. + * + * If the `reportAllChanges` configuration option is set to `true`, the + * `callback` function will be called any time a new `largest-contentful-paint` + * performance entry is dispatched, or once the final value of the metric has + * been determined. + */ +export const onLCP = ( + onReport: (metric: LCPMetric) => void, + opts?: ReportOpts, +) => { + // Set defaults + opts = opts || {}; + + whenActivated(() => { + const visibilityWatcher = getVisibilityWatcher(); + let metric = initMetric('LCP'); + let report: ReturnType; + + const handleEntries = (entries: LCPMetric['entries']) => { + // If reportAllChanges is set then call this function for each entry, + // otherwise only consider the last one. + if (!opts!.reportAllChanges) { + entries = entries.slice(-1); + } + + entries.forEach((entry) => { + // Only report if the page wasn't hidden prior to LCP. + if (entry.startTime < visibilityWatcher.firstHiddenTime) { + // The startTime attribute returns the value of the renderTime if it is + // not 0, and the value of the loadTime otherwise. The activationStart + // reference is used because LCP should be relative to page activation + // rather than navigation start if the page was prerendered. But in cases + // where `activationStart` occurs after the LCP, this time should be + // clamped at 0. + metric.value = Math.max(entry.startTime - getActivationStart(), 0); + metric.entries = [entry]; + report(); + } + }); + }; + + const po = observe('largest-contentful-paint', handleEntries); + + if (po) { + report = bindReporter( + onReport, + metric, + LCPThresholds, + opts!.reportAllChanges, + ); + + const stopListening = runOnce(() => { + if (!reportedMetricIDs[metric.id]) { + handleEntries(po!.takeRecords() as LCPMetric['entries']); + po!.disconnect(); + reportedMetricIDs[metric.id] = true; + report(true); + } + }); + + // Stop listening after input. Note: while scrolling is an input that + // stops LCP observation, it's unreliable since it can be programmatically + // generated. See: https://github.com/GoogleChrome/web-vitals/issues/75 + ['keydown', 'click'].forEach((type) => { + // Wrap in a setTimeout so the callback is run in a separate task + // to avoid extending the keyboard/click handler to reduce INP impact + // https://github.com/GoogleChrome/web-vitals/issues/383 + addEventListener(type, () => whenIdle(stopListening), { + once: true, + capture: true, + }); + }); + + onHidden(stopListening); + + // Only report after a bfcache restore if the `PerformanceObserver` + // successfully registered. + onBFCacheRestore((event) => { + metric = initMetric('LCP'); + report = bindReporter( + onReport, + metric, + LCPThresholds, + opts!.reportAllChanges, + ); + + doubleRAF(() => { + metric.value = performance.now() - event.timeStamp; + reportedMetricIDs[metric.id] = true; + report(true); + }); + }); + } + }); +}; -- cgit v1.2.3