WooCommerce remove outofstock products from related

index.php

add_filter( 'woocommerce_related_products', 'exclude_oos_related_products', 10, 3 );
function exclude_oos_related_products( $related_posts, $product_id, $args ){
   $out_of_stock_product_ids = (array) wc_get_products( array(
         'status'       => 'publish',
         'limit'        => -1,
         'stock_status' => 'outofstock',
         'return'       => 'ids',
   ) );

   $exclude_ids = $out_of_stock_product_ids;

   return array_diff( $related_posts, $exclude_ids );
}