Deduping Google Analytics Transaction Hits - customTask

customModel.js

function () {
  return function (model) {
    var proxyDomain = "https://<yourdomain.com>/collect";
    var proxySendHitTask = function () {
      function pixel(hitPayload) {
        var result = false;
        try {
          document.createElement("img").src = proxyDomain + "?" + hitPayload, result = true
        } catch (e) {}
        return result
      }
      return {
        send: function (hitPayload) {
          var result;
          if (!(result = 2036 >= hitPayload.length && pixel(hitPayload))) {
            result = false;
            try {
              result = navigator.sendBeacon && navigator.sendBeacon(proxyDomain,hitPayload)
            } catch (e) {}
          }
          if (!result) {
            var xhr;
            try {
              window.XMLHttpRequest && "withCredentials" in (xhr = new XMLHttpRequest) && (xhr.open("GET", proxyDomain, true), xhr.setRequestHeader("Content-Type", "text/plain"), xhr.send(hitPayload), result = true)
            } catch (e) {}
          }
          return result || pixel(hitPayload)
        }
      }
    }();
    tracker.set("sendHitTask", function (model) {
      proxySendHitTask.send(model.get("hitPayload"));
    }, true)
  }
}