React 19 API fixes

[cknitt]

Summary

Correct several React 19 and React 19.2 bindings so their ReScript types match the runtime APIs.

Changes

useEffectEvent

Preserve the callback’s complete type:

external useEffectEvent: 'callback => 'callback

The previous binding only supported callbacks returning unit with at most one argument. React allows Effect Events to accept any number of arguments, return any value, and retain the original callback signature.

useFormStatus

Align the returned status with React’s pending and non-pending states:

• Make data nullable when no form submission is active.
• Make method nullable because it is null in the non-pending state.
• Make action nullable when no function action is associated with the form.
• Model action as a one-argument FormData callback instead of a useActionState reducer.
• Remove the unused 'state type parameter that resulted from the incorrect reducer type.

resumeToPipeableStream

Correct the Node.js streaming API:

• Return the {pipe, abort} controller directly instead of a Promise.
• Add a dedicated pipeableStream type.
• Add the Node streaming lifecycle options:
  • onAllReady
  • onShellReady
  • onShellError
• Keep the shared nonce, signal, and onError options.

React returns this controller synchronously; the previous binding incorrectly described it as a promise resolving to a Node stream.

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commit: 79e7139

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Preserve async form action return values

When the parent form uses an async action, including the React.formAction<FormData.t> supported on line 107, useFormStatus().action refers to a function returning promise<unit> at runtime. Typing every status action as FormData.t => unit prevents callers from awaiting or handling that promise and can turn a rejected action into an unhandled rejection; this type should represent both synchronous and asynchronous form actions rather than discarding the return value.

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[cknitt]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. 👍

Reviewed commit: 79e7139dae

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• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

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[Freddy03h]

I prefer keeping the function type with 1 argument, that will cover almost all the use cases of useEffectEvent and adding an unsafe binding for the edge cases : #157 (comment)

[cknitt]

We do have the exact same issue with useCallback, and there we have:

@module("react")
external useCallback: ('f, 'deps) => 'f = "useCallback"

I think we should do the same here for consistency.