Nujabes37

!isset($filter['created_at']['$gt']) ?:
    $dataArray['{date_from}'] = $filter['created_at']['$gt'];
!isset($filter['created_at']['$lt']) ?:
    $dataArray['{date_to}'] = $filter['created_at']['$lt'];

function longStr(string $str, int $j){
    $arrStr = [];
    while ($j < strlen($str)) {
        if(! in_array($str[$j], $arrStr, true)){
            $arrStr[] = $str[$j];
            $j++;
        } else {
            return count($arrStr);
        }
    }
    return count($arrStr);
}