railslove/rack-tracker

<% if trackers.any? %>
<script async src='https://www.googletagmanager.com/gtag/js?id=<%= trackers[0][:id] %>'></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments)};
  gtag('js', new Date());

  <% if set_options %>
    gtag('set', <%= set_options.to_json %>);
  <% end %>

  <% trackers.each do |tracker| %>
    <% pages.each do |page| %>
      gtag('config', '<%= tracker[:id] %>', <%= tracker_options.merge(page.params).to_json %>);
    <% end %>
    gtag('config', '<%= tracker[:id] %>', <%= tracker_options.to_json %>);
  <% end %>

  <% events.each do |event| %>
    gtag('event', '<%= event.action %>', <%= event.params.to_json %>);
  <% end %>
</script>
<% end %>