Add common hook type (Fix #80)

[gugahoa]

No description provided.

[Schmavery]

This is a super slick solution afaict, nice. Any thoughts about reexposing the result type (and any other relevant types) from the ReasonUrql.Hooks module so that users don't have to open another module?

[parkerziegler]

This is great @gugahoa! I agree with @Schmavery, is there a way for us to essentially re-export Types in the Hooks module so that it doesn't have to be opened by the user? Would it be enough to just include UrqlTypes in the definition of module Hooks? Just ping here once you've made the few requested changes 🤗 ❤️

[gugahoa]

I tried to make it not necessary to open Types when opening Hooks, but couldn't accomplish it, any ideas on how to do it?

I tried making a type hookResponse('ret) = UrqlTypes.hookResponse('ret) in each file, or putting it inside module Hooks

Pinging @parkerziegler for re-review

[Schmavery]

@gugahoa I'm surprised that adding type hookResponse('ret) = UrqlTypes.hookResponse('ret) to the Hooks module didn't work. I was playing with it a little earlier, does this help?
https://reasonml.github.io/try?rrjsx=true&reason=LYewJgrgNgpgBAFQJ4AcYGc4F44G8BQccALqvAIbZ4CWAXHNQHbEC+A3ISWXAEbadEAPnABCIAB4AKJsQCUHdvnyhIsOAAkQIANaYcBIqTRxKOZGnQA6UzXozFh7nzNkrzuMLFSZ8pURXQ8ACCVAZEcLDEcABmVJK45hiW1Cyy2AB8DBxEipwBaiKhAhEwUbE48YlWKWlYmdTZcIq5IGiMGlq6HJEkoXRwAIyKPcQATFRekgO+QZbRknIcQA

Basically I reexposed the type using something like this in the Hooks module:

type a = Types.a = {i: int};

[parkerziegler]

@gugahoa can you try the above suggested by @Schmavery? If we get that to work then I think this is set to 🚢

[parkerziegler]

Another thing to bring up while I'm here – do you happen to know how to handle GADTs in the component case? I got it working-ish w/ Subscription, but this syntax will fail the build:

[@react.component]
let make =
    (
      type acc,
      type response,
      type ret,
      ~request: request(ret),
      ~handler: handler(acc, response, ret),
      ~children: subscriptionRenderProps(ret) => React.element,
    ) => {

with the following error:

[1/2] Building src/components/UrqlSubscription.mlast
Fatal error: exception Invalid_argument("react.component calls can only be on function definitions or component wrappers (forwardRef, memo).")
ninja: error: rebuilding 'build.ninja': subcommand failed
error Command failed with exit code 2.

I wonder if there's any easy way around this 🤔

[gugahoa]

@Schmavery thanks for the suggestion, it worked perfectly!
@parkerziegler I remember getting stuck on that error previously, but I don't remember what caused it. Is your work in any branch where we can take a look?

[parkerziegler]

Yep, just pushed it up: https://github.com/FormidableLabs/reason-urql/tree/task/type-inference-gadt-for-subscription Here are the relevant lines: https://github.com/FormidableLabs/reason-urql/blob/task/type-inference-gadt-for-subscription/src/components/UrqlSubscription.re#L53-L80

Basically, I think the [@react.component] flag enforces nothing other than named args in the function signature. It's not the end of the world if we ship one hook and 2 components as well – sometimes that's just the breaks.

[gugahoa]

@parkerziegler seems like you found a bug, I tried to look for any issues that mentioned that, but couldn't find, so I created a new one on the reason-react repo: reasonml/reason-react#452

[parkerziegler]

Thanks @gugahoa. I'm skeptical that we'll get support for it in the near future, so I'll push up a possible solution for us so that we can feature cap v1.