How to make a slug or a friendly URL that contains Arabic characters?

make-slug

/**
 * make_slug
 * @author @AmrMekkawy
 * 
 * based on http://goo.gl/7WULfc & http://goo.gl/P6j345
 * and modified by @AmrMekkawy to be used with Arabic language
 */
if (!function_exists("make_slug")) {
    function make_slug($string = null, $separator = "-") {
        if (is_null($string)) {
            return "";
        }
    
        // Remove spaces from the beginning and from the end of the string
        $string = trim($string);

        // Lower case everything 
        // using mb_strtolower() function is important for non-Latin UTF-8 string | more info: http://goo.gl/QL2tzK
        $string = mb_strtolower($string, "UTF-8");;
    
        // Make alphanumeric (removes all other characters)
        // this makes the string safe especially when used as a part of a URL
        // this has been modified to keep arabic charactrs as well
        $string = preg_replace("/[^a-z0-9_\s-ءاأإآؤئبتثجحخدذرزسشصضطظعغفقكلمنهويةى]/u", "", $string);
    
        // Remove multiple dashes or whitespaces
        $string = preg_replace("/[\s-]+/", " ", $string);
    
        // Convert whitespaces and underscore to the given separator
        $string = preg_replace("/[\s_]/", $separator, $string);
    
        return $string;
    }
}