Calendly Event Listener Code For Google Analytics 4

<script>
window.dataLayer = window.dataLayer ||[];
window.addEventListener('message',
  function(e) {
    if (e.data.event && e.data.event.indexOf('calendly') === 0) {
      window.dataLayer.push({
        'event' : 'calendly',
        'calendly_event' : e.data.event.split('.')[1]
      });
    }
  }
);
</script>

Thanks: Julius Fedorovicius (Code Source)