d8ed5be4f7
* Fix ie11 tests from untranspiled vitals * move vitals into client folder * undo test change
33 lines
980 B
TypeScript
33 lines
980 B
TypeScript
import { useEffect, useRef } from 'react'
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import { NextWebVitalsMetric } from '../pages/_app'
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type ReportWebVitalsCallback = (webVitals: NextWebVitalsMetric) => any
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export const webVitalsCallbacks = new Set<ReportWebVitalsCallback>()
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const metrics: NextWebVitalsMetric[] = []
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export function trackWebVitalMetric(metric: NextWebVitalsMetric) {
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metrics.push(metric)
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webVitalsCallbacks.forEach((callback) => callback(metric))
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}
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export function useExperimentalWebVitalsReport(
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callback: ReportWebVitalsCallback
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) {
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const metricIndexRef = useRef(0)
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useEffect(() => {
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// Flush calculated metrics
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const reportMetric = (metric: NextWebVitalsMetric) => {
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callback(metric)
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metricIndexRef.current = metrics.length
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}
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for (let i = metricIndexRef.current; i < metrics.length; i++) {
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reportMetric(metrics[i])
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}
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webVitalsCallbacks.add(reportMetric)
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return () => {
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webVitalsCallbacks.delete(reportMetric)
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}
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}, [callback])
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}
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