cycat-project-website/_includes/google-analytics.html

{% if jekyll.environment == "production" %}
    {% assign gid = site.env.NETLIFY_GOOGLE_ANALYTICS_ID %}
    {% if gid %}
    <script async src="https://www.googletagmanager.com/gtag/js?id={{ gid }}"></script>
    <script>
      window.dataLayer = window.dataLayer || [];

      function gtag() {
        dataLayer.push(arguments);
      }
      gtag('js', new Date());
      gtag('config', '{{ $gid }}');
    </script>
    {% elsif site.google_analytics_id %}
    <script async src="https://www.googletagmanager.com/gtag/js?id={{ site.google_analytics_id }}"></script>
    <script>
      window.dataLayer = window.dataLayer || [];

      function gtag() {
        dataLayer.push(arguments);
      }
      gtag('js', new Date());
      gtag('config', '{{ site.google_analytics_id }}');
    </script>
    {% endif %}
{% endif %}