Reselect: Investigate Adding Flow Types

[ellbee]

[ellbee]

I've added an initial attempt at this in the flow branch. It concentrates on createSelector. I basically copied the TypeScript typings almost verbatim, and not knowing either of these libraries very well there could be lots of room for improvement.

[threehams]

I won't be able to help here, unfortunately. I'm not familiar enough with Flow, and there's no support for Windows.

[ellbee]

@threehams No worries, I'm just happy you can help with the TypeScript stuff!

[RiddleMan]

Hi all :)
I wanted to cover all libraries that I use in work with Flow. Reselect is one of them.
I didn't know that task is already in progress so I made my own typings version.
https://gist.github.com/RiddleMan/5adf7689bcf3d277473e92ef07961dbb

I'm pretty new with Flow and Open Source (my first contribution).

I think I can start by reviewing your typings and make some comments on them to help land functionality as quick as possible.

[ellbee]

Hey @RiddleMan, that would be great! Thank you

[RiddleMan]

@ellbee
Ok I analyzed both declaration (mine and yours). Mostly we made this in the same way.

1. I've spotted that you forgot to pass equalityCheck?: EqualityChecker as second argument of defaultMemoize
2. createSelectorCreator's first argument is not a selector, but Memoization function which can be just a function.
3. Of course there is lack of createStructuredSelector

There are 2 ways for resolving that. I can use your flow branch and do a pull request with all flow tests or you can do changes on your own :) I have some time so I can finish your work :)

[ellbee]

Hey, thanks for that. I don't have a lot of time at the moment so a PR would be very welcome.

When we have a more complete set of declarations, maybe we should also submit to https://github.com/flowtype/flow-typed to get even more eyes on them?

[RiddleMan]

Ok I've finished work on flow typings. I created some tests and ofc .flow file

I don't know how to proceed to merge this PR #164

[ellbee]

Reselect has typings in the Flow Typed repo so we won't maintain them here.

[alex3165]

@ellbee Why not doing the same for the Typescript type definition file (moving it in definitelyTyped) ? Even better, for a library like Reselect I think it would be worth having the source files written in Flow or Typescript.

[cr0cK]

And redux is shipped with its declarations too, so reselect could be too.

cf https://github.com/reactjs/redux/tree/master/flow-typed