wp-bootstrap-navwalker.php

<?php
/**
* WP Bootstrap Navwalker
*
* @package WP-Bootstrap-Navwalker
*/

/*
* Class Name: WP_Bootstrap_Navwalker
* Plugin Name: WP Bootstrap Navwalker
* Plugin URI:  https://github.com/wp-bootstrap/wp-bootstrap-navwalker
* Description: A custom WordPress nav walker class to implement the Bootstrap 3 navigation style in a custom theme using the WordPress built in menu manager.
* Author: Edward McIntyre - @twittem, WP Bootstrap
* Version: 2.0.5
* Author URI: https://github.com/wp-bootstrap
* GitHub Plugin URI: https://github.com/wp-bootstrap/wp-bootstrap-navwalker
* GitHub Branch: master
* License: GPL-3.0+
* License URI: http://www.gnu.org/licenses/gpl-3.0.txt
*/

/* Check if Class Exists. */
if ( ! class_exists( 'bootstrap_4_walker_nav_menu' ) ) {
	/**
	* WP_Bootstrap_Navwalker class.
	*
	* @extends Walker_Nav_Menu
	*/
	class bootstrap_4_walker_nav_menu extends Walker_Nav_Menu {

		function start_lvl( &$output, $depth ){ // ul
			$indent = str_repeat("\t",$depth); // indents the outputted HTML
			$submenu = ($depth > 0) ? ' sub-menu' : '';
			$output .= "\n$indent<ul class=\"dropdown-menu$submenu depth_$depth\">\n";
		}

		function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ){ // li a span

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

			$li_attributes = '';
			$class_names = $value = '';

			$classes = empty( $item->classes ) ? array() : (array) $item->classes;

			$classes[] = ($args->walker->has_children) ? 'dropdown' : '';
			$classes[] = ($item->current || $item->current_item_anchestor) ? 'active' : '';
			$classes[] = 'nav-item';
			$classes[] = 'nav-item-' . $item->ID;
			if( $depth && $args->walker->has_children ){
				$classes[] = 'dropdown-menu';
			}

			$class_names =  join(' ', apply_filters('nav_menu_css_class', array_filter( $classes ), $item, $args ) );
			$class_names = ' class="' . esc_attr($class_names) . '"';

			$id = apply_filters('nav_menu_item_id', 'menu-item-'.$item->ID, $item, $args);
			$id = strlen( $id ) ? ' id="' . esc_attr( $id ) . '"' : '';

			$output .= $indent . '<li ' . $id . $value . $class_names . $li_attributes . '>';

			$attributes  = ! empty( $item->attr_title ) ? ' title="' . esc_attr($item->attr_title) . '"' : '';
			$attributes .= ! empty( $item->target ) ? ' target="' . esc_attr($item->target) . '"' : '';
			$attributes .= ! empty( $item->xfn ) ? ' rel="' . esc_attr($item->xfn) . '"' : '';
			$attributes .= ! empty( $item->url ) ? ' href="' . esc_attr($item->url) . '"' : '';

			$attributes .= ( $args->walker->has_children ) ? ' class="nav-link dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false"' : ' class="nav-link"';

			$item_output = $args->before;
			$item_output .= ( $depth > 0 ) ? '<a class="dropdown-item"' . $attributes . '>' : '<a' . $attributes . '>';
			$item_output .= $args->link_before . apply_filters( 'the_title', $item->title, $item->ID ) . $args->link_after;
			$item_output .= '</a>';
			$item_output .= $args->after;

			$output .= apply_filters ( 'walker_nav_menu_start_el', $item_output, $item, $depth, $args );
		}
	}
}