/** Checks if provided HTML element is invalid
 *
 * @param {HTMLElement} html_elem
 * @param {string} msg
 * @throws - If provided HTML element is invalid
 * @returns {void}
 */
export declare const check_inv_html_elem: (html_elem: HTMLElement | undefined | null, msg: string) => void;
/** (No throw) error message meant for a parent defaulting to body, only if null or undefined
 *
 * @param what - Can't parent {{ what }}
 * @param [parent]
 * @returns {string}
 */
export declare const err_msg_finisher: (what: string, parent?: HTMLElement) => string;