src/Collection/LeanMenu.php
public function update( $new_instance, $old_instance ) {
		$menus = get_terms( 'nav_menu', array( 'hide_empty' => true ) );

		$selected_menu = isset( $_REQUEST[ $this->get_menu_field_id() ] ) ?
			sanitize_text_field( wp_unslash( $_REQUEST[ $this->get_menu_field_id() ] ) ) : false;

		foreach ( $menus as $menu ) {
			if ( $selected_menu === $menu->slug ) {
				$new_instance['menu'] = $selected_menu;
				break;
			}
		}

		return $new_instance;
	}
public function update( $new_instance, $old_instance ) {
		$menus = get_terms( 'nav_menu', array( 'hide_empty' => true ) );

		$selected_menu = isset( $_REQUEST[ $this->get_menu_field_id() ] ) ?
			sanitize_text_field( wp_unslash( $_REQUEST[ $this->get_menu_field_id() ] ) ) : false;

		foreach ( $menus as $menu ) {
			if ( $selected_menu === $menu->slug ) {
				$new_instance['menu'] = $selected_menu;
				break;
			}
		}

		return $new_instance;
	}
public function update ( $ new_instance , $ old_instance ) { $ menus = get_terms ( 'nav_menu' , array ( 'hide_empty' => true ) ) ; $ selected_menu = isset ( $ _REQUEST [ $ this -> get_menu_field_id ( ) ] ) ? sanitize_text_field ( wp_unslash ( $ _REQUEST [ $ this -> get_menu_field_id ( ) ] ) ) : false ; foreach ( $ menus as $ menu ) { if ( $ selected_menu === $ menu -> slug ) { $ new_instance [ 'menu' ] = $ selected_menu ; break ; } } return $ new_instance ; }
Save the menu slug

@param array $new_instance
@param array $old_instance
@return array
Save the menu slug