new CustomEvent polyfill (new Event) for IE 9, IE10, IE11

custom-event.polyfill.ts

/**
* Modern browsers already support new CustomEvent
* Remember to switch to CustomEvent in your application
*/

// If IE
if (typeof w.CustomEvent !== typeof isNaN) {

    const customEvent = function (event, params) {
        params = params || {bubbles: false, cancelable: false, detail: undefined};
        const evt = document.createEvent("CustomEvent");
        evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail);
        return evt;
    };

    customEvent.prototype = w.Event.prototype;

    w.CustomEvent = customEvent;
}