WordPress Login / Logout Links In Nav Menu
add_filter( 'wp_nav_menu_items', 'add_loginout_link', 10, 2 );
function add_loginout_link( $items, $args ) {
if (is_user_logged_in() && $args->theme_location == 'primary-menu') {
$items .= '<li><a href="'. wp_logout_url() .'">Log Out</a></li>';
}
elseif (!is_user_logged_in() && $args->theme_location == 'primary-menu') {
$items .= '<li><a href="'. site_url('wp-login.php') .'">Log In</a></li>';
}
return $items;
}