Using gtag with Turbolinks

_ga.html.erb

<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=GA_TRACKING_ID"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag() {
    dataLayer.push(arguments);
  }

  document.addEventListener('turbolinks:load', function (event) {
    if (typeof gtag === 'function') {
      gtag('js', new Date());
      gtag('config', 'GA_TRACKING_ID', {
        'page_location': event.data.url
      });
    }
  });
</script>

I had problem with this implementation and AdWords. Paid traffic in Google Analytics had too many sessions/user and very high bounce rate, because Analytics was somehow reseting session of paid traffic. Finally I found code that worked:

          gtag('js', new Date());
          gtag('config', 'GA_TRACKING_ID', {
             'page_path': location.pathname + location.search
          });