Pattern matching event tracking with Fathom Analytics

rei-sponsored-pattern-matching.js

<script>
  document.querySelectorAll('[rel="sponsored"]').forEach(item => {
    item.addEventListener('click', event => {
      let linkUrl = new URL(item.getAttribute('href'), window.location.href);
      // Using the second argument to handle relative URLs
      let currentHostname = window.location.hostname;
      if (linkUrl.hostname !== currentHostname) {
      // If the link's hostname is different from the current page's hostname
      let domainParts = linkUrl.hostname.split('.');
      let domainName = domainParts.length > 1 ? domainParts[domainParts.length - 2] : domainParts[0];
      fathom.trackEvent(`Affiliate: ${domainName}`);
      }
    });
  });
</script>

Referenced in the article, "Fathom Analytics adds dynamic event and goal tracking."