if $chunk_length parameter is specified, the returned array will be broken down * into chunks with each being $chunk_length in length, otherwise each chunk * will be one character in length. * If the $chunk_length length exceeds the length of string, the entire string is returned * as the first (and only) array element. * If the given string is empty, and empty array will be returned. * * @pure */ function chunk(string $string, int $chunk_length = 1): array { if ('' === $string) { return []; } return str_split($string, $chunk_length); }