<?php

defined('ABSPATH') || exit;
function rocket_dns_prefetch($hints, $relation_type)
{
    if (defined('DONOTROCKETOPTIMIZE') && DONOTROCKETOPTIMIZE) {
        return $hints;
    }
    $domains = rocket_get_dns_prefetch_domains();
    if ((bool) $domains) {
        foreach ($domains as $domain) {
            if ('dns-prefetch' === $relation_type) {
                $hints[] = $domain;
            }
        }
    }
    return $hints;
}
add_filter('wp_resource_hints', 'rocket_dns_prefetch', 10, 2);