Added woocommerce_get_featured_product_ids() to retrieve featured products IDs within an array

includes/wc-product-functions.php

@@ -172,6 +172,49 @@ function woocommerce_get_product_ids_on_sale() {
 	return $product_ids_on_sale;
 }
 
+/**
+ * Function that returns an array containing the IDs of the featured products.
+ *
+ * @since 2.1
+ * @access public
+ * @return array
+ */
+function woocommerce_get_featured_product_ids() {
+	
+	// Load from cache
+	$featured_product_ids = get_transient( 'wc_featured_products' );
+
+	// Valid cache found
+	if ( false !== $featured_product_ids )
+		return $featured_product_ids;
+
+	$featured = get_posts( array(
+		'post_type'      => array( 'product', 'product_variation' ),
+		'posts_per_page' => -1,
+		'post_status'    => 'publish',
+		'meta_query'     => array(
+			array(
+				'key' 		=> '_visibility',
+				'value' 	=> array('catalog', 'visible'),
+				'compare' 	=> 'IN'
+			),
+			array(
+				'key' 	=> '_featured',
+				'value' => 'yes'
+			)
+		),
+		'fields' => 'id=>parent'
+	) );
+
+	$product_ids          = array_keys( $featured );
+	$parent_ids           = array_values( $featured );
+	$featured_product_ids = array_unique( array_merge( $product_ids, $parent_ids ) );
+
+	set_transient( 'wc_featured_products', $featured_product_ids );
+
+	return $featured_product_ids;
+}
+
 /**
  * woocommerce_get_product_terms function.
  *