CustomEvent() polyfill

custom-event-polyfill.js

/**
 * CustomEvent() polyfill
 *
 * https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent/CustomEvent#Polyfill
 * https://caniuse.com/#feat=customevent
 * https://developer.mozilla.org/en-US/docs/Web/Guide/Events/Creating_and_triggering_events
 */
(function(){
    if (typeof window.CustomEvent === "function") return false;
    function CustomEvent(event, params) {
        params = params || { bubbles: false, cancelable: false, detail: undefined };
        var evt = document.createEvent('CustomEvent');
        evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail);
        return evt;
    }
    CustomEvent.prototype = window.Event.prototype;
    window.CustomEvent = CustomEvent;
})();