docs: public static Object delete(Object obj, Object id, Context cx,
                                  Scriptable scope, boolean isName)
      {
          Scriptable sobj = toObjectOrNull(cx, obj, scope);
          if (sobj == null) {
              if (isName) {
                  return Boolean.TRUE;
              }
              throw undefDeleteError(obj, id);
          }
          boolean result = deleteObjectElem(sobj, id, cx);
          return wrapBoolean(result);
      }