How to get IDs for objects in menu branch?

Question

Is it possible to print content of all menu items, when displaying menu (or branch of menu as in question about displaying menu branches) ?

Once I click on About Us I wish for new page to display content of all it's children links.

So basically I am looking for a way to get IDs of those posts/pages and use them inside my WP Query.

Answer 1

I am lazy to write supporting logic from scratch so I am reusing functions from linked answer on branches:

/**
 * Retrieve IDs of posts in branch of menu.
 *
 * @param mixed  $menu
 * @param string $branch_title
 *
 * @link http://wordpress.stackexchange.com/questions/2802/display-a-portion-branch-of-the-menu-tree-using-wp-nav-menu
 *
 * @return array
 */
function get_post_ids_from_menu_branch( $menu, $branch_title ) {

    $menu_object = wp_get_nav_menu_object( $menu );
    $menu_items  = wp_get_nav_menu_items( $menu_object->term_id );
    $items       = submenu_limit( $menu_items, (object) array( 'submenu' => $branch_title ) );
    $items       = wp_list_filter( $items, array( 'object' => 'post' ) );
    $ids         = wp_list_pluck( $items, 'object_id' );

    return $ids;
}

// example
var_dump( get_post_ids_from_menu_branch( 'Test menu', 'Level 1' ) );