public static function initials($inputString, array $delimiters = null)
    {
        if (true === StringUtils::isEmpty($inputString)) {
            return $inputString;
        }

        if ((null !== $delimiters) && (0 === \count($delimiters))) {
            return StringUtils::EMPTY_STR;
        }

        $inputStringLen = StringUtils::length($inputString);
        $buffer = array();
        $lastWasGap = true;

        for ($i = 0; $i < $inputStringLen; ++$i) {
            $char = StringUtils::charAt($inputString, $i);

            $delimiter = self::isDelimiter($char, $delimiters);
            if (true === $delimiter) {
                $lastWasGap = true;
            } elseif (true === $lastWasGap) {
                $buffer[] = $char;
                $lastWasGap = false;
            }
        }

        return \implode($buffer);
    }