Retrieve menu items hierarchically in Wordpress

getMenuHierarchically.php

```php

/**
 * Get Menu Items From Location
 *
 * @param $location : location slug given as key in register_nav_menus
 */

function getMenuItemsFromLocation($location) {
	$theme_locations = get_nav_menu_locations();
	$menu_obj = get_term( $theme_locations[$location], 'nav_menu' );
	return is_wp_error($menu_obj) ? [] : getMenuItemsForParent($menu_obj->slug, 0)
}


/**
 * Get Menu Items For Parent
 * 
 * @param $menuSlug : menu slug for the CMS entry (not the key in register_nav_menus)
 * @param $parentId
 * @return array of items formatted as objects with : name / url / children (fetched recursively)
 * object and object_id are used to get custom fields
 */
function getMenuItemsForParent($menuSlug, $parentId) {
	$tmpItems = wp_get_nav_menu_items($menuSlug);
	$items = [];
	foreach ( $tmpItems as $tmpItem ) {
		$item = new stdClass;
	        if ($tmpItem->menu_item_parent == $parentId) {
	            $item->title = $tmpItem->title;
	            $item->url = $tmpItem->url;
	            $item->object = $tmpItem->object;
	            $item->object_id = $tmpItem->object_id;
	    		$item->children = getMenuItemsForParent($menuSlug, $tmpItem->ID);
	    		$items[] = $item;
	        }
	}
	return $items;
}

/**
 * Usage
 */
 
$menuItems = getMenuItemsFromLocation('footer_menu');

// will return :
[
	'name' => 'Menu item 1'
	'url' => '/my-post-type/my-url-1'
	'children' => [
		'name' => 'Menu item 2'
		'url' => '/external-custom-link'
		'children' => []
	],
	// etc...
]
```