Add custom link to menu to logged in users only

gistfile1.txt

// Filter wp_nav_menu() to add additional links
function kallyasChildExtendMenuNav($items, $args = null)
{
    // Make sure the arguments are passed correctly
    if(! empty($args) && is_object($args))
    {
        // Make sure the WooCommerce plugin exists and is activated
        if( class_exists('WooCommerce') )
        {
            // Make sure we're updating the correct menu: top nav
            if(isset($args->menu) && isset($args->menu->slug) && $args->menu->slug == 'top-nav')
            {
                // Make sure the user is logged in
                if( is_user_logged_in())
                {
                    // Add the link to MyAccount page
                    $myaccount_page_id = get_option( 'woocommerce_myaccount_page_id' );
                    if ( $myaccount_page_id ) {
                        $myaccount_page_url = get_permalink( $myaccount_page_id );
                        // add the My Account link to the end of the menu
                        $items = $items . '<li><a href="'.$myaccount_page_url.'">'.__('My Account', 'zn_framework').'</a></li>';
                    }
                }
            }
        }
    }
    return $items;
}
add_filter( 'wp_nav_menu_items', 'kallyasChildExtendMenuNav', 2, 99 );