WordPress: Manage featured posts using WordPress menus

featured-posts-pattern-helper-functions.php

<?php
/**
 * Get the featured posts for a specific menu location 
 *
 * @param string $theme_location As defined in the register_nav_menus call
 *
 * @return array|bool|mixed Array of Post IDs
 */
function my_theme_get_featured_posts( $theme_location = '' ) {
	
	$last_changed = wp_cache_get_last_changed( 'my_group_menus' );
	
	$cache_key = 'menu_'. md5( $theme_location ) . $last_changed;

	if ( false === ( $featured = wp_cache_get( $cache_key, 'my_theme' ) ) ) {

		$locations = get_nav_menu_locations();

		if( empty( $theme_location ) || !isset( $locations[ $theme_location ] ) ) {
			return array();
		}

		$menu = get_term( $locations[ $theme_location ], 'nav_menu' );

		if( empty( $menu->term_id ) ) {
			return array();
		}

		$menu_items = wp_get_nav_menu_items( $menu->term_id );

		if( empty( $menu_items ) || !is_array( $menu_items ) ) {
			return array();
		}

		$featured = array();

		foreach( $menu_items as $item ) {
			// here I'm filtering to only get post objects
			if( $item->type != 'post_type' ) {
				continue;
			}
			$featured[] = $item->object_id;

		}


		wp_cache_set( $cache_key, $featured, 'my_theme', DAY_IN_SECONDS );

	}

	return $featured;
}

/**
 * Hook on wp_update_nav_menu to burn a new 'last_changed' timestamp
 */
function my_theme_update_menu() {
	wp_cache_set( 'last_changed', microtime(), 'my_group_menus'  );
}
add_action( 'wp_update_nav_menu', 'my_theme_update_menu' );

featured-posts-pattern-template.php

<?php
/**
 * On a WordPress template, get the featured posts for the slider
 */
$featured = my_theme_get_featured_posts( 'slider' );
global $post;
?>
<section class="hero">

	<?php if( !empty( $featured ) && is_array( $featured ) ): ?>

		<div class="hero-slider">

			<?php 
			foreach( $featured as $slide ) : 
      
				$post = get_post( $slide );
				setup_postdata( $post );
				get_template_part( 'parts/slide-hero', get_post_type() );

			endforeach; wp_reset_postdata(); ?>

		</div>

	<?php endif; ?>

</section>