Wait until all async is done

wait.js

 var arr = [];
        function allDone() { console.log('All done') }
        function replaceCallback(callback) {
            if (typeof callback !== 'function') return callback;
            arr.push(callback);
            return function () {
                var pos = arr.indexOf(callback);
                if (pos > -1) arr.splice(pos, 1);
                var res = callback.apply(this, arguments);
                if (arr.length === 0) allDone();
                return res;
            }
        }
        function replaceAsync(fn, callbackPos) {
            return function (...args) {
                args[callbackPos] = replaceCallback(args[callbackPos]);
                return fn.apply(this, args);
            }
        }

        window.setTimeout = replaceAsync(setTimeout, 0);
        // window.setImmediate = replaceAsync(setImmediate, 0);
        window.requestAnimationFrame = replaceAsync(requestAnimationFrame, 0);
        Promise.prototype.then = replaceAsync(Promise.prototype.then, 0);
        // todo: second callback
        Promise.prototype.catch = replaceAsync(Promise.prototype.catch, 0);

        var onreadystatechange = Object.getOwnPropertyDescriptor(XMLHttpRequest.prototype, 'onreadystatechange');
        // todo check all callback, onerror, onload etc
        Object.defineProperty(XMLHttpRequest.prototype, 'onreadystatechange', {
            get() {
                return onreadystatechange.get.call(this);
            },
            set(cb) {
                // todo: check that is fully loaded
                onreadystatechange.set.call(this, replaceCallback(cb));
            }
        })

        setTimeout(function () { console.log('setTimeout done'); }, 2000);
        var xhr = new XMLHttpRequest();
        xhr.open('GET', 'https://api.github.com/users/octocat/orgs', true);
        xhr.send();
        xhr.onreadystatechange = function () {
            console.log('xhr done');
        }
        fetch('https://api.github.com/users/octocat/orgs').then(res => res.json()).then(() => {
            console.log('fetch done');
        });