JavaScript ancestor class list

ancestors.js

/**
* Returns the list of ancestor classes.
*
* Example:
*   ancestors(HTMLElement) .map (e => e.name || e.constructor.name)
*   => [ "HTMLElement", "Element", "Node", "EventTarget", "Function", "Object" ]
*/
function ancestors (anyclass)
{
  switch (true) {
  case (anyclass === undefined): return;
  case (anyclass === null): return [];
  default:
    return [anyclass, ...(ancestors (Object.getPrototypeOf (anyclass)))];
  }
}