Custom Walker anchor tag not inheriting attributes

Question

So I am just now learning and playing with custom walkers and I came across this really helpful Stack Overflow question. So I implemented the answer in that answer and added this to my functions.php of my theme (which btw is an underscores theme if that helps)

class Custom_Walker_Nav_Menu extends Walker_Nav_Menu {
  function start_el ( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
    // Copy all the start_el code from source, and modify
        $indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
        $classes = empty( $item->classes ) ? array() : (array) $item->classes;
        $classes[] = 'menu-item-' . $item->ID;
        /**      * Filter the CSS class(es) applied to a menu item's list item element.
         * @since 3.0.0
         * @since 4.1.0 The `$depth` parameter was added.
         * @param array  $classes The CSS classes that are applied to the menu item's `<li>` element.
         * @param object $item    The current menu item.
         * @param array  $args    An array of {@see wp_nav_menu()} arguments.
         * @param int    $depth   Depth of menu item. Used for padding.      */
        $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args, $depth ) );
        $class_names = $class_names ? ' class="' . esc_attr( $class_names ) . '"' : '';
        /**      * Filter the ID applied to a menu item's list item element.
         * @since 3.0.1
         * @since 4.1.0 The `$depth` parameter was added.
         * @param string $menu_id The ID that is applied to the menu item's `<li>` element.
         * @param object $item    The current menu item.
         * @param array  $args    An array of {@see wp_nav_menu()} arguments.
         * @param int    $depth   Depth of menu item. Used for padding.      */
        $id = apply_filters( 'nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args, $depth );
        $id = $id ? ' id="' . esc_attr( $id ) . '"' : '';
        $output .= $indent . '<li class="menu-item">';
        $atts = array();
        $atts['title']  = ! empty( $item->attr_title ) ? $item->attr_title : '';
        $atts['target'] = ! empty( $item->target )     ? $item->target     : '';
        $atts['rel']    = ! empty( $item->xfn )        ? $item->xfn        : '';
        $atts['href']   = ! empty( $item->url )        ? $item->url        : '';
        /**      * Filter the HTML attributes applied to a menu item's anchor element.
         *
         * @since 3.6.0
         * @since 4.1.0 The `$depth` parameter was added.
         *
         * @param array $atts {
         *     The HTML attributes applied to the menu item's `<a>` element, empty strings are ignored.
         *
         *     @type string $title  Title attribute.
         *     @type string $target Target attribute.
         *     @type string $rel    The rel attribute.
         *     @type string $href   The href attribute.
         * }
         * @param object $item  The current menu item.
         * @param array  $args  An array of {@see wp_nav_menu()} arguments.
         * @param int    $depth Depth of menu item. Used for padding.        */
        $atts = apply_filters( 'nav_menu_link_attributes', $atts, $item, $args, $depth );
        $attributes = '';
        foreach ( $atts as $attr => $value ) {
            if ( ! empty( $value ) ) {
                $value = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
                $attributes .= ' ' . $attr . '="' . $value . '"';
            }
        }
        $item_output = $args->before;
        $item_output .= '<a'. $attributes .'><canvas ' . $id . '>';
        /** This filter is documented in wp-includes/post-template.php */
        $item_output .= $args->link_before . apply_filters( 'the_title', $item->title, $item->ID ) . $args->link_after;
        $item_output .= '</canvas></a>';
        $item_output .= $args->after;
        /**      * Filter a menu item's starting output.
         * The menu item's starting output only includes `$args->before`, the opening `<a>`,
         * the menu item's title, the closing `</a>`, and `$args->after`. Currently, there is
         * no filter for modifying the opening and closing `<li>` for a menu item.
         *
         * @since 3.0.0
         *
         * @param string $item_output The menu item's starting HTML output.
         * @param object $item        Menu item data object.
         * @param int    $depth       Depth of menu item. Used for padding.
         * @param array  $args        An array of {@see wp_nav_menu()} arguments.        */
        $output .= apply_filters( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
    }
    /**  * Ends the element output, if needed.
     * @see Walker::end_el()
     * @since 3.0.0
     * @param string $output Passed by reference. Used to append additional content.
     * @param object $item   Page data object. Not used.
     * @param int    $depth  Depth of page. Not Used.
     * @param array  $args   An array of arguments. @see wp_nav_menu()   */ 
    //end pasted code
  }
  function end_el( &$output, $item, $depth = 0, $args = array() ) {
    // Copy all the end_el code from source, and modify 
    $output .= "</li>\n";   
    //end pasted code
  }

Then I changed my wp_nav_menu in the header.php to:

wp_nav_menu( array( 'theme_location' => 'primary', 
'menu_id' => 'primary-menu', 'walker' => new Custom_Walker_Nav_Menu ) );

The issue is is that the HTML is now structured like I want, however when the custom walker is implemented the anchor tags lose the text between them (which is the title of the page) and their href attribute, so they're no longer a link to the page I need them to go to.

I feel like maybe it's something involving the $attributes array but I'm not sure how to go about fixing it.

Any assistance is appreciated!

Answer 1

This looks like just a misunderstanding about the canvas element - if a browser supports canvas, any elements you place inside a canvas simply won't display, i.e. they're fallback elements for browsers that don't support the canvas element. (That inlcudes text nodes)

I looked through the script and it looks fine - except for stuff being placed inside a canvas. links should be something like: Link Title

And you can manipulate the canvas positioning through css/javascript depending on what you're doing with them.