Listen outbonds link from current view, and send to google analytics

Analytics.html

<!-- Here you can add your Google Analytics Tracking code. If you do so, do not
forget to set the include_analytics attribute to true on the _config.yml file -->
<script async src="https://www.googletagmanager.com/gtag/js?id=G-XB3ENLMJ9V"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag() { dataLayer.push(arguments); }
  gtag('js', new Date());

  gtag('config', 'G-XB3ENLMJ9V');
  gtag('send', 'pageview');

  function _gaLt(event) {

    /* If GA is blocked or not loaded, or not main|middle|touch click then don't track */
    // if (!ga.hasOwnProperty("loaded") || ga.loaded != true || (event.which != 1 && event.which != 2)) {
    //   return;
    // }

    var el = event.srcElement || event.target;

    /* Loop up the DOM tree through parent elements if clicked element is not a link (eg: an image inside a link) */
    while (el && (typeof el.tagName == 'undefined' || el.tagName.toLowerCase() != 'a' || !el.href)) {
      el = el.parentNode;
    }

    /* if a link with valid href has been clicked */
    if (el && el.href) {

      var link = el.href;

      /* Only if it is an external link */
      if (link.indexOf(location.host) == -1 && !link.match(/^javascript\:/i)) {

        /* Is actual target set and not _(self|parent|top)? */
        var target = (el.target && !el.target.match(/^_(self|parent|top)$/i)) ? el.target : false;

        /* Assume a target if Ctrl|shift|meta-click */
        if (event.ctrlKey || event.shiftKey || event.metaKey || event.which == 2) {
          target = "_blank";
        }

        var hbrun = false; // tracker has not yet run

        /* HitCallback to open link in same window after tracker */
        var hitBack = function () {
          /* run once only */
          if (hbrun) return;
          hbrun = true;
          window.location.href = link;
        };

        if (target) { /* If target opens a new window then just track */
          gtag("event", "Outgoing Links", {
            "to": link,
            "from": document.location.pathname + document.location.search
          });
        } else { /* Prevent standard click, track then open */
          event.preventDefault ? event.preventDefault() : event.returnValue = !1;
          /* send event with callback */
          gtag("event", "Outgoing Links", {
            "to": link,
            "from": document.location.pathname + document.location.search,
            "hitCallback": hitBack
          });

          gtag("event", "page_view")

          /* Run hitCallback again if GA takes longer than 1 second */
          setTimeout(hitBack, 1000);
        }
      }
    }
  }

  var _w = window;
  /* Use "click" if touchscreen device, else "mousedown" */
  var _gaLtEvt = ("ontouchstart" in _w) ? "click" : "mousedown";
  /* Attach the event to all clicks in the document after page has loaded */
  _w.addEventListener ? _w.addEventListener("load",
    function () { document.body.addEventListener(_gaLtEvt, _gaLt, !1) }, !1)
    : _w.attachEvent && _w.attachEvent("onload",
      function () { document.body.attachEvent("on" + _gaLtEvt, _gaLt) });
</script>