hextra/layouts/partials/google-analytics.html

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

    gtag("config", "{{ . }}");
  </script>
{{ end -}}