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| author | altaf-creator <dev@altafcreator.com> | 2025-11-09 11:15:19 +0800 |
|---|---|---|
| committer | altaf-creator <dev@altafcreator.com> | 2025-11-09 11:15:19 +0800 |
| commit | 8eff962cab608341a6f2fedc640a0e32d96f26e2 (patch) | |
| tree | 05534d1a720ddc3691d346c69b4972555820a061 /frontend-old/node_modules/web-vitals/dist/modules/onTTFB.js | |
pain
Diffstat (limited to 'frontend-old/node_modules/web-vitals/dist/modules/onTTFB.js')
| -rw-r--r-- | frontend-old/node_modules/web-vitals/dist/modules/onTTFB.js | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/frontend-old/node_modules/web-vitals/dist/modules/onTTFB.js b/frontend-old/node_modules/web-vitals/dist/modules/onTTFB.js new file mode 100644 index 0000000..9d12af4 --- /dev/null +++ b/frontend-old/node_modules/web-vitals/dist/modules/onTTFB.js @@ -0,0 +1,79 @@ +/* + * 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 { initMetric } from './lib/initMetric.js'; +import { onBFCacheRestore } from './lib/bfcache.js'; +import { getNavigationEntry } from './lib/getNavigationEntry.js'; +import { getActivationStart } from './lib/getActivationStart.js'; +import { whenActivated } from './lib/whenActivated.js'; +/** Thresholds for TTFB. See https://web.dev/articles/ttfb#what_is_a_good_ttfb_score */ +export const TTFBThresholds = [800, 1800]; +/** + * Runs in the next task after the page is done loading and/or prerendering. + * @param callback + */ +const whenReady = (callback) => { + if (document.prerendering) { + whenActivated(() => whenReady(callback)); + } + else if (document.readyState !== 'complete') { + addEventListener('load', () => whenReady(callback), true); + } + else { + // Queue a task so the callback runs after `loadEventEnd`. + setTimeout(callback, 0); + } +}; +/** + * Calculates the [TTFB](https://web.dev/articles/ttfb) value for the + * current page and calls the `callback` function once the page has loaded, + * along with the relevant `navigation` performance entry used to determine the + * value. The reported value is a `DOMHighResTimeStamp`. + * + * Note, this function waits until after the page is loaded to call `callback` + * in order to ensure all properties of the `navigation` entry are populated. + * This is useful if you want to report on other metrics exposed by the + * [Navigation Timing API](https://w3c.github.io/navigation-timing/). For + * example, the TTFB metric starts from the page's [time + * origin](https://www.w3.org/TR/hr-time-2/#sec-time-origin), which means it + * includes time spent on DNS lookup, connection negotiation, network latency, + * and server processing time. + */ +export const onTTFB = (onReport, opts) => { + // Set defaults + opts = opts || {}; + let metric = initMetric('TTFB'); + let report = bindReporter(onReport, metric, TTFBThresholds, opts.reportAllChanges); + whenReady(() => { + const navigationEntry = getNavigationEntry(); + if (navigationEntry) { + // The activationStart reference is used because TTFB should be + // relative to page activation rather than navigation start if the + // page was prerendered. But in cases where `activationStart` occurs + // after the first byte is received, this time should be clamped at 0. + metric.value = Math.max(navigationEntry.responseStart - getActivationStart(), 0); + metric.entries = [navigationEntry]; + report(true); + // Only report TTFB after bfcache restores if a `navigation` entry + // was reported for the initial load. + onBFCacheRestore(() => { + metric = initMetric('TTFB', 0); + report = bindReporter(onReport, metric, TTFBThresholds, opts.reportAllChanges); + report(true); + }); + } + }); +}; |
