NavWalker với Bootstrap 4.4 thu gọn với đúng lớp cha mẹ “.collapsed” và các lớp “.active”

/**
* Class Name: Bootstrap_Collapse_NavWalker
* GitHub URI: https://gist.github.com/mtx-z/db34d68364108c0285e6e3e721630846
* Description: A custom WordPress 5.3 nav walker class for Bootstrap 4.4 nav menus in a custom theme using the WordPress built in menu manager
* Version: 0.1
* Author: Mtxz
* Source: https://github.com/filipszczepanski/wp-bootstrap4-collapse-navwalker
* Tested only with 1 sublevel, but should work with as many level as you want
*/

/**
* Usage
* <?php if (has_nav_menu('my_menu')): ?>
* <nav>
* <?php
* wp_nav_menu([
* 'theme_location' => 'my_menu',
* 'echo' => true,
* 'container' => false,
* 'container_class' => '',
* 'container_id' => '',
* 'menu_class' => 'w-auto', //example
* 'menu_id' => 'shop_menu_nav', //example
* 'fallback_cb' => 'wp_page_menu',
* 'before' => '',
* 'after' => '',
* 'link_before' => '',
* 'link_after' => '',
* 'items_wrap' => '<ul id="%1$s" class="%2$s" aria-labelledby="shop_menu_nav">%3$s</ul>',
* 'depth' => 0,
* 'walker' => new Bootstrap_Collapse_NavWalker()
* ]); ?>
* </nav>
* <?php endif; ?>
*/

/**
* Class Bootstrap_Collapse_NavWalker
*/
class Bootstrap_Collapse_NavWalker extends Walker_Nav_Menu
{
var $parent_item_id = 0;
var $parent_item_depth = false;
var $parent_has_current_child = false;
var $currentItem = null;

/**
* Starts the list before the elements are added.
*
* @since 3.0.0
*
* @see Walker::start_lvl()
*
* @param string $output Passed by reference. Used to append additional content.
* @param int $depth Depth of menu item. Used for padding.
* @param stdClass $args An object of wp_nav_menu() arguments.
*/
public function start_lvl(&$output, $depth = 0, $args = [])
{
if (isset($args->item_spacing) && 'discard' === $args->item_spacing) {
$t = '';
$n = '';
} else {
$t = "\t";
$n = "\n";
}
$indent = str_repeat($t, $depth);
$collapse_in_class = $this->parent_has_current_child ? 'in' : '';
$collapse_id = '';
if (!empty($this->parent_item_id)) {
$collapse_id = $this->collapse_id($this->parent_item_id);
}

//if is current parent and have children: open collapse
if (null !== $this->currentItem
&& isset($this->currentItem->classes)
&& in_array('current-menu-parent', $this->currentItem->classes, true)
&& in_array('menu-item-has-children', $this->currentItem->classes, true)) {
$collapse_in_class .= ' show';
}

$collapse_block = sprintf('<ul id="%s" class="nav collapse %s" aria-labelledby="link_%s" role="tabpanel">' . "\n", $collapse_id, $collapse_in_class, $collapse_id);
$output .= $n . $indent . $collapse_block . $n;
}

/**
* Ends the list of after the elements are added.
*
* @since 3.0.0
*
* @see Walker::end_lvl()
*
* @param string $output Passed by reference. Used to append additional content.
* @param int $depth Depth of menu item. Used for padding.
* @param stdClass $args An object of wp_nav_menu() arguments.
*/
public function end_lvl(&$output, $depth = 0, $args = [])
{
if (isset($args->item_spacing) && 'discard' === $args->item_spacing) {
$t = '';
$n = '';
} else {
$t = "\t";
$n = "\n";
}
$indent = str_repeat($t, $depth);
$output .= "$indent</ul>{$n}";
}

/**
* Starts the element output.
*
* @since 3.0.0
* @since 4.4.0 The {@see 'nav_menu_item_args'} filter was added.
*
* @see Walker::start_el()
*
* @param string $output Passed by reference. Used to append additional content.
* @param WP_Post $item Menu item data object.
* @param int $depth Depth of menu item. Used for padding.
* @param stdClass $args An object of wp_nav_menu() arguments.
* @param int $id Current item ID.
*/
public function start_el(&$output, $item, $depth = 0, $args = [], $id = 0)
{
$this->currentItem = $item;
$classes = empty($item->classes) ? [] : (array)$item->classes;
if ($this->parent_item_depth !== $depth || $this->parent_item_id !== $item->ID) {
$this->parent_item_depth = $depth;
$this->parent_item_id = $item->ID;
$this->parent_has_current_child = (in_array('current-menu-ancestor', $classes, true));
$this->start_el($output, $item, $depth, $args, $item->ID);
} else {
if (isset($args->item_spacing) && 'discard' === $args->item_spacing) {
$t = '';
$n = '';
} else {
$t = "\t";
$n = "\n";
}
$indent = ($depth) ? str_repeat($t, $depth) : '';
$this->parent_item_depth = 0;
$classes[] = 'menu-item-' . $item->ID;
$classes[] = 'nav-item';

if (in_array('current-menu-item', $classes, true)) {
$classes[] = ' active';
}

/**
* Filters the arguments for a single nav menu item.
*
* @since 4.4.0
*
* @param stdClass $args An object of wp_nav_menu() arguments.
* @param WP_Post $item Menu item data object.
* @param int $depth Depth of menu item. Used for padding.
*/
// $args = apply_filters( 'nav_menu_item_args', $args, $item, $depth );

/**
* Filters 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 WP_Post $item The current menu item.
* @param stdClass $args An object of wp_nav_menu() arguments.
* @param int $depth Depth of menu item. Used for padding.
*/
$class_names = implode(' ', apply_filters('nav_menu_css_class', array_filter($classes), $item, $args, $depth));
$class_names = $class_names ? ' class="' . esc_attr($class_names) . '"' : '';
/**
* Filters 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 WP_Post $item The current menu item.
* @param stdClass $args An object of 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) . '"' : '';
$item_output = $indent . '<li' . $id . $class_names . '>';
$atts = [];
$atts[ 'title' ] = !empty($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) ? $item->url : '';
if ($depth === 0) {
$atts[ 'class' ] = 'nav-link';
} elseif ($depth > 0) {
$atts[ 'class' ] = 'link-item';
}
if ($args && isset($args->walker) && $args->walker->has_children) {
$atts[ 'data-toggle' ] = 'collapse';
$atts[ 'aria-expanded' ] = 'false';
$atts[ 'aria-controls' ] = $this->collapse_id($item->ID);
// $atts['data-parent'] = '#nav-panel-left';
$atts[ 'role' ] = 'tab';
$atts[ 'href' ] = '#' . $this->collapse_id($item->ID);
$atts[ 'id' ] = 'link_' . $this->collapse_id($item->ID);
}
if (is_array($item->classes)
&& in_array('current-menu-item', $item->classes, true)
&& in_array('nav-item', $item->classes, true)) {
$atts[ 'class' ] .= ' active';
}

/**
* Filters 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 WP_Post $item The current menu item.
* @param stdClass $args An object of 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);

/**
* Is parent item and not active: collapse.
* If is a parent and active, do not add "collapsed" class so it'll be in "open state"
*/
if (in_array('menu-item-has-children', $item->classes, true)
&& !in_array('current-menu-parent', $item->classes, true)) {
$atts[ 'class' ] .= ' collapsed';
}

$attributes = '';
foreach ($atts as $attr => $value) {
if (!empty($value)) {
$value = ('href' === $attr) ? esc_url($value) : esc_attr($value);
$attributes .= ' ' . $attr . '="' . $value . '"';
}
}
/** This filter is documented in wp-includes/post-template.php */
$title = apply_filters('the_title', $item->title, $item->ID);
/**
* Filters a menu item's title.
*
* @since 4.4.0
*
* @param string $title The menu item's title.
* @param WP_Post $item The current menu item.
* @param stdClass $args An object of wp_nav_menu() arguments.
* @param int $depth Depth of menu item. Used for padding.
*/
$title = apply_filters('nav_menu_item_title', $title, $item, $args, $depth);
$item_output .= $args->before;
$item_output .= '<a' . $attributes . '>';
$item_output .= $args->link_before . $title . $args->link_after;
$item_output .= '</a>';
$item_output .= $args->after;

/**
* Filters 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 WP_Post $item Menu item data object.
* @param int $depth Depth of menu item. Used for padding.
* @param stdClass $args An object of wp_nav_menu() arguments.
*/
$output .= apply_filters('walker_nav_menu_start_el', $item_output, $item, $depth, $args);
}
}

/**
* Ends the element output, if needed.
*
* @since 3.0.0
*
* @see Walker::end_el()
*
* @param string $output Passed by reference. Used to append additional content.
* @param WP_Post $item Page data object. Not used.
* @param int $depth Depth of page. Not Used.
* @param stdClass $args An object of wp_nav_menu() arguments.
*/
public function end_el(&$output, $item, $depth = 0, $args = [])
{
if (isset($args->item_spacing) && 'discard' === $args->item_spacing) {
$t = '';
$n = '';
} else {
$t = "\t";
$n = "\n";
}
$output .= "</li>{$n}";
}

private function collapse_id($nav_id)
{
return 'collapse_' . $nav_id;
}
} // Bootstrap_Collapse_NavWalker