/**
 * **Usage:**
 *
 * `aquireId();`
 * – returns a valid unique DOM id string that can be safely assigned to an element.
 *
 * `aquireId(prefDefaultIdString);`
 * – returns a valid unique DOM id based on `prefDefaultIdString` (appending/autoincrementing a trailing integer if needed)
 *
 * `aquireId(elm);`
 * – returns the value of elm.id -- automatically assigning a unique id first, if needed.
 *
 * `aquireId(elm, prefDefaultIdString);`
 * – returns the value of elm.id -- if needed automatically assigning a unique id based on `prefDefaultIdString`.
 */
export default function aquireId(el?: string | Element | Array<Element> | NodeListOf<Element> | null, prefDefaultId?: string): string;