Add resolver "findAllExportedComponentDefinitions"

[ZauberNerd]

This resolver is basically a direct copy of the
"findExportedComponentDefinition" resolver including the tests.
The most significant difference is, that this resolver does not throw
when it encounters more than one component definition.
It adds all found component definitions into an array (deduplicated)
and returns that array at the end of execution.

[fkling]

This is great, thank you! I was just thinking about this the other day.

[ZauberNerd]

Ah, great. Glad to see things go into upstream :)
I'm currently re-thinking my approach to a living style guide generator for react components (https://github.com/nerdlabs/schaufenster) and I think I'll just go with react-docgen and a bunch of custom handlers instead. I started writing a couple of them already here for file-based dependencies and here for the export of the component but those are not really related to this project, so I didn't create PRs for them but will extract them into their own npm modules to allow others to use them too.

[fkling]

I didn't create PRs for them but will extract them into their own npm modules to allow others to use them too.

That's perfect. I will actually post something very soon about how I see react-docgen moving forward, and that's exactly what I had in mind!

[fkling]

Could you export this handler from src/resolver/index.js as well?

[fkling]

Seems like you need to change this type annotation to Array<NodePath>.

[ZauberNerd]

I tried changing it yesterday and got different errors. I'll look into it when I have a bit more time.