HelperFunctions.php

<?php

if (!function_exists('applicationUrl')) {

    /**
     * Will return the fully qualified domain name for the correct environment etc
     *
     * @param string $sub_domain
     * @param string $path
     * @return string
     */

    function applicationUrl($sub_domain = 'app', $path = null)
    {
        $related_link = parse_url(config('app.url'));

        $final_url = $related_link['scheme'] . '://' . $sub_domain . '.' . $related_link['host'];

        if (!is_null($path)) {
            $final_url .= '/' . ltrim($path, '/');
        }

        return $final_url;
    }
}