Trigger function without jQuery

trigger.js

const trigger = (element, eventName) => {
    let event;

    if (document.createEvent) {
        event = document.createEvent("HTMLEvents");
        event.initEvent(eventName, true, true);
    } else {
        event = document.createEventObject();
        event.eventType = eventName;
    }

    event.eventName = eventName;
    (document.createEvent) ?
        element.dispatchEvent(event) :
        element.fireEvent("on" + event.eventType, event);
};