If you’re trying to put spaces in the actual module name, that probably isn’t wise (and may not be allowed by npm). If you want your package named “foo bar baz” and someone types
npm install foo bar baz, then either npm will attempt to install a package named “foo”, a package named “bar”, and a package named “baz” … or just give you an error for having extra stuff on the line. In either case, it won’t install your package. Go along with the convention of having hyphens instead of spaces and things will be much easier.
(Yes, I understand that things with spaces can either be quoted or escaped … but it is still a pain that the end user shouldn’t have to deal with.)