After Wordpress 4.8 upgrade, wp_nav_menu() string search / replace not working

Question

Before upgrading to Wordpress 4.8, I could do a string search and replace on the wp_nav_menu(). I had a few sites running 4.7.5 and code was working. Soon as upgrading code below did nothing.

    <?php
    $args = array(
         'theme_location'  => $nav_name,
         'container'  => 'nav',
         'items_wrap' => '<ul>%3$s</ul>',
         'container_class' => " ",
         'echo' => false
    );
    $nav = wp_nav_menu( $args );
    $nav = str_replace('<ul class="sub-menu">', '<div class="mobile-drop"><ul>', $nav);
    $match = '</ul>'."\n".'</li>';
    $nav = str_replace($match, '</ul></div></li>', $nav);
    echo $nav;
    ?>

Now post 4.8, it doesn't replace the "sub-menu" with my class called "mobile-drop". When I look at the html I do see an outputted "sub-menu" with double quotes.

Answer 1

I found that Wordpress added an extra space.

<ul  class="sub-menu"> 

so the search and replace could not be done correctly. If you look in the code inspector (developer tools) you won't see the extra space. Once going to view source code (command + shift + U), I noticed the actual output code had the extra space. Hope this will help someone with similar problem.