Update exported PropTypes

[taion]

I'm not convinced that we get anything out of exporting PropTypes. They're at least documented now, thanks to @lPadier's #3203, but I think we ought to consider dropping them.

With the possible exception of location, which is a matter of history rather than here anyway, they're not really applicable to users of this library, and things like history are even deprecated.

Analogous to how react-intl handles it, we should export routerShape as a top-level export. The other exports like location, to the extent they are required, should sit in history.

[agundermann]

👍 In my opinion, importing prop types from other modules seems counter-productive. If a component uses location.pathname, for example, the component should be explicit about it (location: shape with pathname: string). By keeping prop types local, the component is more resistant to outside changes, e.g. if the location shape changed, the validation would fail, which it wouldn't with imported prop types.

In cases where a component only passes things along to other components, it should be sufficient to define it as an object or "any".

I wonder how common this is among react libraries.

[taion]

I've never seen any other React libraries that export propTypes. I've never even heard of anybody using the exported propTypes here until #3203.

[ryanflorence]

not sure how things made it into that list, but original intention was people to be able to add a contextTypes: { router: routerPropType } for their components that need the router.

[taion]

That would make sense, but we've already extensively documented router: React.PropTypes.object, and I feel like that's adequate; enough that we don't need exported prop types.

[taion]

@rickharrison Care to elaborate? 😛

[rickharrison]

I do use some of them personally. My thought was why take them out if they are already there considering it's so small. But, I guess if you don't want to maintain them I see why you would. I could also easily just include a similar file like that in my own project, but I'd have to duplicate it across our many react-router based apps.

[timdorr]

IMHO I think most people are better served by a real typing system, such as TypeScript or Flow. PropTypes' duck typing never seemed that helpful to me, personally.

Looks like we need to update our PropTypes anyways. Given they're out of date, I would say we get rid of them.

[taion]

Right, IMO the main thing is that they've just gotten quite out-of-date.

Plus the types for things like locations are owned by history anyway.

[ryanflorence]

PropTypes are super valuable, but I'm not sure we need to export any of them except router

[taion]

We're not currently exporting a router prop type, though.

[taion]

I just found a counterexample. react-intl exports a shape. As I'm currently using react-intl, I am selfishly declaring for the sake of consistency that we should do the same in React Router.

I'm now in favor of continuing to export prop types, though perhaps with a slightly different API.

[taion]

Updated OP with my current thinking here.