private function getType(string $file): string
	{
		$css = '/\.(css|less)$/';
		$js = '/\.js$/';

		if (preg_match($css, $file)) {
			return self::CSS;
		} elseif (preg_match($js, $file)) {
			return self::JS;
		}
		throw new InvalidArgumentException("Unknown assets file '$file'");
	}