Next.js

import { useEffect } from 'react'
import { useRouter } from 'next/router'

export default function MyApp({ Component, pageProps }) {
  const router = useRouter();

  useEffect(() => {
    let originUrl;

    // Keep track of where we're navigating from (for the referrer)
    const handleRouteChangeStart = (url) => {
      originUrl = document.location.href;
    };

    const handleRouteChangeComplete = (url) => {
      window.revgems('trackPageView', { referrer: originUrl }); // 👈 TRACK PAGE VIEW IN REVGEMS
    };

    router.events.on('routeChangeStart', handleRouteChangeStart);
    router.events.on('routeChangeComplete', handleRouteChangeComplete);

    // If the component is unmounted, unsubscribe from the event with the `off` method:
    return () => {
      router.events.off('routeChangeStart', handleRouteChangeStart);
      router.events.off('routeChangeComplete', handleRouteChangeComplete);
    };
  }, [router.events]);

  return
}