Monitoring AJAX calls to API with GA reporting for Timing and Errors

gistfile1.js

// ...

function ajaxRequest(url, done, error){ ... }

//...

realAjaxRequest = ajaxRequest;
ajaxRequest = monitoredAjaxRequest;

function monitoredAjaxRequest(url, done, error){

   var startTime = new Date().getTime();
	
   function monitoredDone(response){
   	setTimeout(function(){ done(response); }, 100);
	var endTime = new Date().getTime();
        var timeSpent = endTime - startTime;
        ga('send', 'timing', 'justanswer.api', 'done', timeSpent, document.location.hostname);
   }

   function monitoredError(details){
   	setTimeout(function(){ error(details); }, 100);
	var endTime = new Date().getTime();
        var timeSpent = endTime - startTime;
        var description = 'justanswer.api error:' + details.message;
        ga('send', 'timing', 'justanswer.api', 'error', timeSpent, document.location.hostname);
        ga('send', 'exception', { 'exDescription': description, 'exFatal': true, 'appName': 'lowlander' });
   }

   return realAjaxRequest(url, monitoredDone, monitoredError);

}