Improve selectorForSlice

[dpikt]

• Test case when slice is undefined
• Fix parameter types in docs
• (optional) consider second argument for post-path slice

[rkillackey]

@dpikt Not sure I understand the last bullet point here. Couldn't you just give the full path including the "post-path slice"?

[dpikt]

Yeah it's not really necessary. I was just brainstorming. Most of our selectors on kubo look like this:

const selectors = {
    facilities: select('facilities.success'),
    patients: select('patients.success'),
    surveys: select('surveys.success'),
}

so I thought it might be nice to remove some of that redundancy. I would just shelve the idea for now though, since it's not really a big issue.

[rkillackey]

Ohh, gotcha. Do you want to open a new issue for the backlog?

[dpikt]

Eh I would just ignore it for now. I don't really see it popping up again tbh