xml/http listener with js

jsXMLHTTPListener.js

if (typeof window.jsXMLHTTPListener === 'undefined') {
    let jsXMLHTTPListener = {
        isCallFinishedStatus: 1,
        pointerSize: 0,
        pointerFinishSize: 0,
        isCallFinished: function() {
            return 1 === this.isCallFinishedStatus;
        },
        setCallFinished: function(i = 0) {
            this.isCallFinishedStatus = i;
        },
        bindEvents: function(i, t) {
            var e = t.XMLHttpRequest.prototype.send;
            t.XMLHttpRequest.prototype.send = function() {
                i.setCallFinished(0);
                var n = this;
                i.pointerSize++;
                var s = t.setInterval(function() {
                    4 == n.readyState && (i.pointerFinishSize++, i.pointerSize === i.pointerFinishSize ? i.setCallFinished(1) : i.setCallFinished(0), clearInterval(s));
                }, 1);
                return e.apply(this, [].slice.call(arguments));
            };
        },
        init: function() {
            this.bindEvents(this, window);
        },
    };
    (window.jsXMLHTTPListener = jsXMLHTTPListener), window.jsXMLHTTPListener.init();
    let a = window.jsXMLHTTPListener.isCallFinished();
    console.log(a);
} else {
    let a = window.jsXMLHTTPListener.isCallFinished();
    console.log(a);
}
//usage

setInterval(() => {
  let a = window.jsXMLHTTPListener.isCallFinished();
  console.log(a);
}, 100);