React Enzyme Testing - CustomEvent is not defined

I been testing this component but it outputs CustomEvent is not defined: My Code below

emitEvent(detail) {
        Utils.setCustomEvent();
        const event = new CustomEvent(detail.eventName, {
            detail,
            bubbles: true,
            cancelable: false,
        });
        document.dispatchEvent(event);
}

Enzyume Test code: How can I test the new CustomEvent dunction which is in EmitEvent()

describe('<ScheduleComp />', () => {
    describe('render ', () => {
        const detail = {
            key: 'productOffering',
            state: 'update',
            eventName: 'data',
            cardName: 'data',
        }
        const wrapper = shallow(<ScheduleComp {...ScheduleCompData} />);
        assert.isNotNull(wrapper);
        it('Should verify if', () => {
            const emitEvent = spy();
            const CustomEvent = spy();

            const component = new ScheduleComp({ ...ScheduleCompData,
                emitEvent,
                CustomEvent
            });

            component.flipCard(event);
            component.emitEvent(detail);
            component.CustomEvent(detail.eventName);
        });

    });
});