https://www.mystampingstudio.ca/1723204579/checkout/PromiseAccumulator.js

1(function (window) {
2    var EVENT_SUCCESS = 'success';
3    var EVENT_ERROR = 'error';
4
5    var PromiseAccumulatorBus = function () {
6        var queue = {};
7
8        this.addEventListener = function (event, callback) {
9            if (!queue[event]) {
10                queue[event] = [];
11            }
12            queue[event].push(callback);
13        };
14
15        this.trigger = function (event, data) {
16            if (!queue[event]) {
17                return;
18            }
19
20            queue[event].forEach(function (callback) {
21                callback(data);
22            });
23        };
24
25        this.hasListeners = function () {
26            return queue[EVENT_SUCCESS] && queue[EVENT_SUCCESS].length > 0;
27        };
28    };
29
30    var PromiseAccumulatorBusManager = function () {
31        var bus = new PromiseAccumulatorBus();
32
33        this.reCreateBus = function () {
34            var current = bus;
35
36            bus = new PromiseAccumulatorBus();
37
38            return current;
39        };
40
41        this.addEventListener = function (event, callback) {
42            bus.addEventListener(event, callback);
43        };
44
45        this.hasListeners = function () {
46            return bus.hasListeners();
47        };
48    };
49
50    var PromiseAccumulator = function (callback) {
51        var busManager = new PromiseAccumulatorBusManager();
52        var running = false;
53
54        var run = function () {
55            if (running) {
56                return Promise.resolve();
57            }
58
59            running = true;
60            var currentBus = busManager.reCreateBus();
61
62            return callback().then(function (result) {
63                currentBus.trigger(EVENT_SUCCESS, result);
64            }).catch(function (e) {
65                currentBus.trigger(EVENT_ERROR, e);
66            }).finally(function () {
67                running = false;
68
69                if (busManager.hasListeners()) {
70                    run();
71                }
72            });
73        };
74
75        this.getPromise = function () {
76            var promise = new Promise(function (resolve, reject) {
77                busManager.addEventListener(EVENT_SUCCESS, resolve);
78                busManager.addEventListener(EVENT_ERROR, reject);
79            });
80
81            run();
82
83            return promise;
84        };
85    };
86
87    window.PromiseAccumulator = PromiseAccumulator;
88})(window);