Namespaced Vuex modules with Folder structure possible?

[DFSebastian]

Hi,
I get the following error in console when trying to use the namespaced syntax from the documentation combined with a folder.
TypeError: this.$store.getters[getterType] is not a function

I do have a parent folder "foo" where my store javascript files are.
I tried solving this by using

...mapFields('foo/brake', 
        [
            'item.diameter',
        ]
),

but this throws the error mentioned above. Is there any other aproach that I am missing?
Kind regards