WordPress filter for setting the proper CSS classes on post type archive menu items

ArchiveMenuFix.php

<?php
	/* 
	*	Archive page in menu fix
	*	(requires menu item URL to be "/slug/")
	*/
	add_filter('nav_menu_css_class', function($classes, $item) {
		global $wp_query;

		// Loop through all the post types
		foreach(get_post_types(null, 'objects') as $name => $post_type) {
			
			// Check if rewrite slug is set
			if(isset($post_type->rewrite) && $item->url === '/'. $post_type->rewrite['slug'] .'/') {
				// Set CSS classes to appropriate item
				$classes = array('menu-item', 'menu-item-type-post_type', 'menu-item-object-page');
				
				// If on archive page, add appropriate CSS class
				if(is_post_type_archive($name)) $classes[] = 'current_page_item';

				// If on single post page, add appropriate CSS class
				if(is_singular($name)) $classes[] = 'current_page_parent';
			}
		}
		
		// Remove active class on blog menu item if CPT
		if(get_option('page_for_posts') == $item->object_id && !is_singular('post')) {
			for($i = 0; $i < count($classes); $i++) {
				if($classes[$i] === 'current_page_parent')
					unset($classes[$i]);
			}
		}

		return $classes;
	}, 10, 2);