}
      case 'LCP': {
        // handle LCP results
      }
      // ...
    }
  })
}
Usage on Vercel
Vercel Speed Insights are automatically configured on Vercel deployments, and don't require the use of useReportWebVitals. This hook is useful in local development, or if you're using a different analytics service.
Sending results to external systems
You can send results to any endpoint to measure and track
real user performance on your site. For example:
 useReportWebVitals((metric) => {
  const body = JSON.stringify(metric)
  const url = 'https://example.com/analytics'
 
  // Use `navigator.sendBeacon()` if available, falling back to `fetch()`.
  if (navigator.sendBeacon) {
    navigator.sendBeacon(url, body)
  } else {