In this case, since the backslash is in a string, it's escaping the period, which does nothing. So it becomes in regex `/[.0-9]/` which matches anything. In order to keep the period escaped in the regex, you have to escape the backslash in a string. JSHint noticed this error.

However, there's no reason this regex needs to be built with the constructor. It's not building the string from variables. I didn't pay attention when fixing it, I was just cleaning up jshint warnings.