Script for counting open AJAX and fetch calls

AjaxFetchWatcher.js

// intercepts AJAX and fetch calls and provides a global status on open calls

var AjaxFetchWatcher = {};
AjaxFetchWatcher.countOfOpenRequests  = 0;

AjaxFetchWatcher.stillOpen = function(){
	return AjaxFetchWatcher.countOfOpenRequests > 0;
};

// intercept AJAX
// thank you https://stackoverflow.com/questions/10783463/javascript-detect-ajax-requests
(function() {
    var proxied = window.XMLHttpRequest.prototype.send;
    window.XMLHttpRequest.prototype.send = function() {
		AjaxFetchWatcher.countOfOpenRequests += 1;
		var pointer = this;
        var intervalId = window.setInterval(function(){
                if (pointer.readyState != 4){
					return;
                }
				AjaxFetchWatcher.countOfOpenRequests -= 1;
                //Here is where you can add any code to process the response.
                //If you want to pass the Ajax request object, pass the 'pointer' below
                clearInterval(intervalId);
        }, 0.3);
        return proxied.apply(this, [].slice.call(arguments));
    };
})();

// intercept fetch
(function() {
    var proxied = window.fetch;
    window.fetch = function() {
		AjaxFetchWatcher.countOfOpenRequests += 1;
		var pointer = this;
		return proxied([].slice.call(arguments)).then(a => {
			AjaxFetchWatcher.countOfOpenRequests -= 1;
		}
		).catch( a=>
		{
			AjaxFetchWatcher.countOfOpenRequests -= 1;	
		}
		);        
    };
})();