Manual use of Walker_Category class

Question

Trying to create a menu with category terms as I read in the WP docs "Using Walker Manually": https://codex.wordpress.org/Class_Reference/Walker

$menu_items = get_categories();
$walk = new \Walker_Category();
print_r( $walk->walk( $menu_items, -1 ) );

I get this warning:

Notice: Undefined index: use_desc_for_title in /srv/www/my-site.com/current/web/wp/wp-includes/class-walker-category.php on line 114

What is the right way to use Walker_category class?

Answer 1

the Walker_Category class you are using requires 3 params in walk() method, the third param will be use_desc_for_title value (this is due to how Walker_Category::start_el() method is written).

In other words, to use the walk() method without generating a notice you should change your last line to

print_r( $walk->walk( $menu_items, -1, -1 ) );

The third param is a boolean:

• "-1" (or false) - will remove the "title" attribute from the generated menu links
• "1" ( or true) - will make the menu use category description for the title attribute.