wordpress expose menus to the rest api

Question

Hi I'm trying to expose the WordPress menus to the rest api, but I want to make it generic, so I can crate expose any menus with the same code, but something is wrong with my code, t always show Json.pase error, I don't know how to solve this.

here is my code.

//define all the menu positions I need
$menus = array(
  'main-menu' =>  __( 'Main Menu' ),
  'other-menu' =>  __( 'Other Menu' )
);

function register_menus() {
  //register the menus in the backend
  global $menus;
  register_nav_menus($menus);
}
add_action( 'init', 'register_menus' );


add_action( 'rest_api_init', function () {
    // create custom route to expose the menus
    register_rest_route( 'wp_ang/v1', '/menu', array(
        'methods' => 'GET',
        'callback' => 'get_menu_items',
      )
    );
  }
);

function get_menu_items() {
    // callback to get menus and its items
    global $menus;
    $rest_menu = [];
    foreach ($menus as $key => $value){
      $menu_name = $key;
      $menu_location = get_nav_menu_locations( );
      $menu = wp_get_nav_menu_object( $menu_location[$menu_name] );
      $menu_items = wp_get_nav_menu_items( $menu->term_id );
    }
    return $menus;
}

Then I have this error as a result:

SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data