implements::getData

public function getData(): string
{
	$delimiter = $this->pickupDelimiter();
	$decodedFields = $this->decodeFields();

	$decodedFields = array_filter($decodedFields, static function($value) {
		return (!empty($value) && !is_array($value) && !is_object($value));
	});

	$data =
		static::FORMAT_IDENTIFIER
		. static::FORMAT_VERSION
		. $this->charsetCode
	;

	foreach ($this->getMandatoryFieldNames() as $fieldName)
	{
		$data .= $delimiter . $fieldName . static::VALUE_DELIMITER . ($decodedFields[$fieldName] ?? '');
		unset ($decodedFields[$fieldName]);
	}

	foreach ($decodedFields as $fieldName => $value)
	{
		$data .= $delimiter . $fieldName . static::VALUE_DELIMITER . $value;
	}

	return $data;
}