remove all submenus from plugin

Question

Is there a way to un register all submenus at once instead of using the code below?

remove_submenu_page('myplugin', 'sub-page-1'); 
remove_submenu_page('myplugin', 'sub-page-2'); 
remove_submenu_page('myplugin', 'sub-page-3'); 
remove_submenu_page('myplugin', 'sub-page-4'); 
remove_submenu_page('myplugin', 'sub-page-5');
...
... 

The idea is...

remove_submenu_page('myplugin', all);??? 

Answer 1

Not without touching the global $submenu directly (which I wouldn't recommend - using only purposefully exposed APIs provides, in general, better stability).

However, if you wanted a function to remove all submenus:

/**
 * Removes all submenus of given menu item
 *
 * @param string $menu_slug The slug of the parent menu to remove submenus of
 */
function wpse137406_remove_submenus( $menu_slug ) {
    global $submenu;

    if ( isset( $submenu[$menu_slug] ) ){
         unset( $submenu[$menu_slug] );
    }
}