在只有一个

Question

我只想在前一个或下一个显示时将特定的CSS添加到链接/元素中（当用户在第一个或最后一个帖子中时，仅显示一个）

js

/*  Back/Next navigation */     
function my_previous_next_post() {
// retrieve the value for next post link
$next_string = "← Previous post";
ob_start(); 
next_post_link("%link", $next_string);
$next_link = ob_get_clean(); 

// retrieve the value for previous post link
$previous_string = "Next post →";
ob_start(); 
previous_post_link("%link", $previous_string);
$previous_link = ob_get_clean(); 

// build output
$return = PHP_EOL . '<div id="next-previous" class="row">' . PHP_EOL;

// display previous link if any
if ($previous_link) {
    $return .= '<div class="col-6 order-2 nav-previous">'. PHP_EOL;
    $return .= $previous_link. PHP_EOL;
    $return .= '</div>'. PHP_EOL;
}

// display next link if any
if ($next_link) {
    $return .= '<div class="col-6 order-1 nav-next">'. PHP_EOL;
    $return .=  $next_link . PHP_EOL;
    $return .= '</div>'. PHP_EOL;
}

$return .= '</div>';

return $return;
}

add_shortcode('backNext-links', 'my_previous_next_post');