createPortal.tsx

import * as React from 'react';
import * as ReactDOM from 'react-dom';

interface IPortalContentProps {
    children: React.ReactNode;
}

const createPortal = () => {
    const portalRef: React.RefObject<HTMLDivElement> = React.createRef();

    const Placeholder: React.FC = () => <div ref={portalRef} />;

    const Content: React.FC<IPortalContentProps> = ({ children }): undefined | React.ReactPortal => {
        return portalRef.current && ReactDOM.createPortal(children, portalRef.current);
    };

    return { Placeholder, Content };
};

export default createPortal;