741ef9032c
### Experimental Introduce `next/vitals` and `useExperimentalWebVitalsReport` API which is not limited by `_app`. `pages/index.js` ```jsx import { useExperimentalWebVitalsReport } from 'next/vitals' export default function Index() { useExperimentalWebVitalsReport((metric) => { // handle metric... }) return 'sup' } ```
89 lines
2.5 KiB
TypeScript
89 lines
2.5 KiB
TypeScript
/* global location */
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import {
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getCLS,
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getFCP,
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getFID,
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getLCP,
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getTTFB,
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Metric,
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ReportHandler,
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} from 'next/dist/compiled/web-vitals'
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const initialHref = location.href
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let isRegistered = false
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let userReportHandler: ReportHandler | undefined
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function onReport(metric: Metric): void {
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if (userReportHandler) {
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userReportHandler(metric)
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}
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// This code is not shipped, executed, or present in the client-side
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// JavaScript bundle unless explicitly enabled in your application.
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//
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// When this feature is enabled, we'll make it very clear by printing a
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// message during the build (`next build`).
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if (
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process.env.NODE_ENV === 'production' &&
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// This field is empty unless you explicitly configure it:
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process.env.__NEXT_ANALYTICS_ID
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) {
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const body: Record<string, string> = {
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dsn: process.env.__NEXT_ANALYTICS_ID,
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id: metric.id,
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page: window.__NEXT_DATA__.page,
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href: initialHref,
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event_name: metric.name,
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value: metric.value.toString(),
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speed:
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'connection' in navigator &&
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(navigator as any)['connection'] &&
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'effectiveType' in (navigator as any)['connection']
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? ((navigator as any)['connection']['effectiveType'] as string)
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: '',
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}
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const blob = new Blob([new URLSearchParams(body).toString()], {
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// This content type is necessary for `sendBeacon`:
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type: 'application/x-www-form-urlencoded',
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})
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const vitalsUrl = 'https://vitals.vercel-insights.com/v1/vitals'
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// Navigator has to be bound to ensure it does not error in some browsers
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// https://xgwang.me/posts/you-may-not-know-beacon/#it-may-throw-error%2C-be-sure-to-catch
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const send = navigator.sendBeacon && navigator.sendBeacon.bind(navigator)
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function fallbackSend() {
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fetch(vitalsUrl, {
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body: blob,
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method: 'POST',
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credentials: 'omit',
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keepalive: true,
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// console.error is used here as when the fetch fails it does not affect functioning of the app
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}).catch(console.error)
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}
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try {
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// If send is undefined it'll throw as well. This reduces output code size.
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send!(vitalsUrl, blob) || fallbackSend()
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} catch (err) {
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fallbackSend()
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}
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}
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}
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export default (onPerfEntry?: ReportHandler): void => {
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// Update function if it changes:
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userReportHandler = onPerfEntry
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// Only register listeners once:
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if (isRegistered) {
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return
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}
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isRegistered = true
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getCLS(onReport)
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getFID(onReport)
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getFCP(onReport)
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getLCP(onReport)
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getTTFB(onReport)
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}
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