t.
	 *
	 * @since 5.9.0
	 *
	 * @param int             $menu_id The menu id to update.
	 * @param WP_REST_Request $request Full details about the request.
	 * @return bool True if the auto add setting was successfully updated.
	 */
	protected function handle_auto_add( $menu_id, $request ) {
		if ( ! isset( $request['auto_add'] ) ) {
			return true;
		}

		$nav_menu_option = (array) get_option( 'nav_menu_options', array( 'auto_add' => array() ) );

		if ( ! isset( $nav_menu_option['auto_add'] ) ) {
			$nav_menu_option['auto_add'] = array();
		}

		$auto_add = $request['auto_add'];

		$i = array_search( $menu_id, $nav_menu_option['auto_add'], true );

		if ( $auto_add && false === $i ) {
			$nav_menu_option['auto_add'][] = $menu_id;
		} elseif ( ! $auto_add && false !== $i ) {
			array_splice( $nav_menu_option['auto_add'], $i, 1 );
		}

		$update = update_option( 'nav_menu_options', $nav_menu_option );

		/** This action is documented in wp-includes/nav-menu.php */
		do_action( 'wp_update_nav_menu', $menu_id );

		return $update;
	}

	/**
	 * Returns the names of the locations assigned to the menu.
	 *
	 * @since 5.9.0
	 *
	 * @param int $menu_id The menu id.
	 * @return string[] The locations assigned to the menu.
	 */
	protected function get_menu_locations( $menu_id ) {
		$locations      = get_nav_menu_locations();
		$menu_locations = array();

		foreach ( $locations as $location => $assigned_menu_id ) {
			if ( $menu_id === $assigned_menu_id ) {
				$menu_locations[] = $location;
			}
		}

		return $menu_locations;
	}

	/**
	 * Updates the menu's locations from a REST request.
	 *
	 * @since 5.9.0
	 *
	 * @param int             $menu_id The menu id to update.
	 * @param WP_REST_Request $request Full details about the request.
	 * @return true|WP_Error True on success, a WP_Error on an error updating any of the locations.
	 */
	protected function handle_locations( $menu_id, $request ) {
		if ( ! isset( $request['locations'] ) ) {
			return true;
		}

		$menu_locations = get_registered_nav_menus();
		$menu_locations = array_keys( $menu_locations );
		$new_locations  = array();
		foreach ( $request['locations'] as $location ) {
			if ( ! in_array( $location, $menu_locations, true ) ) {
				return new WP_Error(
					'rest_invalid_menu_location',
					__( 'Invalid menu location.' ),
					array(
						'status'   => 400,
						'location' => $location,
					)
				);
			}
			$new_locations[ $location ] = $menu_id;
		}
		$assigned_menu = get_nav_menu_locations();
		foreach ( $assigned_menu as $location => $term_id ) {
			if ( $term_id === $menu_id ) {
				unset( $assigned_menu[ $location ] );
			}
		}
		$new_assignments = array_merge( $assigned_menu, $new_locations );
		set_theme_mod( 'nav_menu_locations', $new_assignments );

		return true;
	}

	/**
	 * Retrieves the term's schema, conforming to JSON Schema.
	 *
	 * @since 5.9.0
	 *
	 * @return array Item schema data.
	 */
	public function get_item_schema() {
		$schema = parent::get_item_schema();
		unset( $schema['properties']['count'], $schema['properties']['link'], $schema['properties']['taxonomy'] );

		$schema['properties']['locations'] = array(
			'description' => __( 'The locations assigned to the menu.' ),
			'type'        => 'array',
			'items'       => array(
				'type' => 'string',
			),
			'context'     => array( 'view', 'edit' ),
			'arg_options' => array(
				'validate_callback' => function ( $locations, $request, $param ) {
					$valid = rest_validate_request_arg( $locations, $request, $param );

					if ( true !== $valid ) {
						return $valid;
					}

					$locations = rest_sanitize_request_arg( $locations, $request, $param );

					foreach ( $locations as $location ) {
						if ( ! array_key_exists( $location, get_registered_nav_menus() ) ) {
							return new WP_Error(
								'rest_invalid_menu_location',
								__( 'Invalid menu location.' ),
								array(
									'location' => $location,
								)
							);
						}
					}

					return true;
				},
			),
		);

		$schema['properties']['auto_add'] = array(
			'description' => __( 'Whether to automatically add top level pages to this menu.' ),
			'context'     => array( 'view', 'edit' ),
			'type'        => 'boolean',
		);

		return $schema;
	}
}