WordPress navigation walker customized for Bulma

wordpress-bulma-walker.php

class Bulmaa_Nav_Walker extends Walker_Nav_Menu {
	    public function start_lvl(&$output, $depth = 0, $args = array()) {

	        $output .= '';
	    }

	    public function end_lvl(&$output, $depth = 0, $args = array()) {
	        $output .= '';
	    }

	    public function start_el(&$output, $item, $depth = 0, $args = array(), $id = 0) {

	        if ($this->hasChildren($item)) {
	            $output .= $this->startDropdownButton($item);
	        } else {
	            $output .= $this->getLinkButton($item);
	        }

	    }

	    public function end_el(&$output, $item, $depth = 0, $args = array()) {

	        if ($this->hasChildren($item)) {
	            $output .= $this->endDropdownButton($item);
	        } else {
	            $output .= '';
	        }
	    }

	    public function hasChildren($item) {
	        if (in_array("menu-item-has-children", $item->classes)) {
	            return true;
	        }

	        return false;
	    }

	    public function getLinkButton($item) {
	        $url         = $item->url ?? '';
	        $classes     = empty($item->classes) ? array() : (array) $item->classes;
	        $class_names = '';

	        if (in_array('current-menu-item', $classes)) {
	            $class_names .= 'is-active';
	        }

	        $button = sprintf("<a href='%s' class='navbar-item %s'>%s</a>", $url, $class_names, $item->title);

	        return $button;
	    }

	    public function startDropdownButton($item) {
	        $url         = $item->url ?? '';
	        $classes     = empty($item->classes) ? array() : (array) $item->classes;
	        $class_names = '';

	        if (in_array('current-menu-item', $classes)) {
	            $class_names .= 'is-active';
	        }

	        $button = sprintf("<a href='%s' class='navbar-link %s'>%s</a>", $url, $class_names, $item->title);

	        $dropdown = sprintf("<div class='navbar-item has-dropdown is-hoverable'>%s", $button);

	        $dropdown .= "<div class='navbar-dropdown is-boxed'>";
	        return $dropdown;
	    }

	    public function endDropdownButton($item) {
	        return "</div></div>";
		}
}

/*
Usage:
wp_nav_menu(
	array(
		'theme_location'  => 'primary',
		'menu'            => '',
		'walker'          => new Bulma_Nav_Walker(),
		'container' => false,
		'items_wrap'      => '<div class="navbar-end">%3$s</div>',
	)
);
*/