这是我编辑菜单项的代码，也许它可以帮助您：

class SB_Menu_Walker extends Walker_Nav_Menu {

 /**
 * What the class handles.
 *
 * @see Walker::$tree_type
 * @since 3.0.0
 * @var string
 */
public $tree_type = array(\'post_type\', \'taxonomy\', \'custom\');

/**
 * Database fields to use.
 *
 * @see Walker::$db_fields
 * @since 3.0.0
 * @todo Decouple this.
 * @var array
 */
public $db_fields = array(\'parent\' => \'menu_item_parent\', \'id\' => \'db_id\');

/**
 * Starts the list before the elements are added.
 *
 * @see Walker::start_lvl()
 *
 * @since 3.0.0
 *
 * @param string $output Passed by reference. Used to append additional content.
 * @param int    $depth  Depth of menu item. Used for padding.
 * @param array  $args   An array of arguments. @see wp_nav_menu()
 */
public function start_lvl(&$output, $depth = 0, $args = array()) {
    $indent = str_repeat("\\t", $depth);
    $output .= "\\n$indent<ul class=\\"sub-menu\\">\\n";
}

/**
 * Ends the list of after the elements are added.
 *
 * @see Walker::end_lvl()
 *
 * @since 3.0.0
 *
 * @param string $output Passed by reference. Used to append additional content.
 * @param int    $depth  Depth of menu item. Used for padding.
 * @param array  $args   An array of arguments. @see wp_nav_menu()
 */
public function end_lvl(&$output, $depth = 0, $args = array()) {
    $indent = str_repeat("\\t", $depth);
    $output .= "$indent</ul>\\n";
}

/**
 * Start the element output.
 *
 * @see Walker::start_el()
 *
 * @since 3.0.0
 *
 * @param string $output Passed by reference. Used to append additional content.
 * @param object $item   Menu item data object.
 * @param int    $depth  Depth of menu item. Used for padding.
 * @param array  $args   An array of arguments. @see wp_nav_menu()
 * @param int    $id     Current item ID.
 */
public function start_el(&$output, $item, $depth = 0, $args = array(), $id = 0) {
    // Lấy thông tin title của menu item
    $menu_title = $item->title;
    $menu_title_slug = SB_Core::sanitize_slug($menu_title);

    $indent =($depth) ? str_repeat("\\t", $depth) : \'\';

    $classes = empty($item->classes) ? array() : (array) $item->classes;
    $classes[] = \'menu-item-\' . $item->ID;

    // Thêm class vào menu item
    $classes[] = \'menu-\' . $menu_title_slug;

    /**
     * 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\' . $id . $class_names .\'>\';

    $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 .\'>\';

    $item_output .= $args->link_before;

    $item_output = apply_filters(\'sb_theme_menu_item_output_link_text_before\', $item_output, $item);

    $link_text = apply_filters(\'the_title\', $item->title, $item->ID);
    $item_output .= apply_filters(\'sb_theme_menu_item_output_link_text\', $link_text, $item);

    if(SB_Tool::use_menu_item_description() && !empty($item->description)) {
        $item_output .= \'<span class="description">\' . $item->description . \'</span>\';
    }

    $item_output = apply_filters(\'sb_theme_menu_item_output_link_text_after\', $item_output, $item);

    $item_output .= $args->link_after;

    $item_output .= \'</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  $args   An array of arguments. @see wp_nav_menu()
 */
public function end_el(&$output, $item, $depth = 0, $args = array()) {
    $output .= "</li>\\n";
}

}