dist/event-target-shim.js
function defineCustomEventTarget(eventNames) {
    /** CustomEventTarget */
    function CustomEventTarget() {
        EventTarget.call(this);
    }

    CustomEventTarget.prototype = Object.create(EventTarget.prototype, {
        constructor: {
            value: CustomEventTarget,
            configurable: true,
            writable: true,
        },
    });

    for (let i = 0; i < eventNames.length; ++i) {
        defineEventAttribute(CustomEventTarget.prototype, eventNames[i]);
    }

    return CustomEventTarget
}
function defineCustomEventTarget(eventNames) {
    /** CustomEventTarget */
    function CustomEventTarget() {
        EventTarget.call(this);
    }

    CustomEventTarget.prototype = Object.create(EventTarget.prototype, {
        constructor: {
            value: CustomEventTarget,
            configurable: true,
            writable: true,
        },
    });

    for (let i = 0; i < eventNames.length; ++i) {
        defineEventAttribute(CustomEventTarget.prototype, eventNames[i]);
    }

    return CustomEventTarget
}
Define a custom EventTarget with event attributes.
@param {string[]} eventNames Event names for event attributes.
@returns {EventTarget} The custom EventTarget.
@private