draft is typed as any when using produce() within React setState()

[oscar-b]

🐛 Bug Report

draft is typed as any when using produce() within React setState(), instead of inferring the type. Older versions of immer does this properly, but newer one doesn't. As far as I can see, v2.1.5 (and before) works, after that it doesn't.

Link to repro

Working:

https://codesandbox.io/s/adoring-https-rsgqg?file=/src/App.tsx

Not working (only change is version of immer to v8.0.0):

https://codesandbox.io/s/flamboyant-lehmann-ms3fw?file=/src/App.tsx

Expected behavior

I expect the draft to get a proper type.

Environment

• Immer version: 8.0.0
• Typescript 4.0.3 (in Codesandbox)
• I filed this report against the latest version of Immer
• Occurs with setUseProxies(true)
• Occurs with setUseProxies(false) (ES5 only)

[mweststrate]

Might suffer from the same problem as demonstrated in this playground, meaning we could possibly apply the same solution. See also: mobxjs/mobx#2740

[iChenLei]

typedef change

Before v2.1.5 https://github.com/immerjs/immer/blob/v2.1.5/src/immer.d.ts#L71-L107
After v2.1.5 https://github.com/immerjs/immer/blob/v2.2.0/src/immer.d.ts#L72-L107
In your case, you match the Curried producer

> v2.1.5

	<
		Recipe extends (...args: any[]) => any,
		Params extends any[] = Parameters<Recipe>,
		T = Params[0]
	>(
		recipe: Recipe
	): <Base extends Immutable<T>>(
		base: Base,
		...rest: Tail<Params>
	) => Produced<Base, ReturnType<Recipe>>

recipe => Recipe => Recipe extends (...args: any[]) => any

<= v2.1.5

    /** Curried producer with no default value */
    <T = any, Rest extends any[] = [], Return = void>(
        recipe: (this: Draft<T>, draft: Draft<T>, ...rest: Rest) => Return
    ): (base: Immutable<T>, ...rest: Rest) => Produced<T, Return>

recipe => (this: Draft<T>, draft: Draft<T>, ...rest: Rest) => Return

@mweststrate Sir, Maybe this is why current version immer can't infer type correctly. I think it's not same with the mobx case.

append

• The useState typedef

  function useState<S>(initialState: S | (() => S)): [S, Dispatch<SetStateAction<S>>];
  type Dispatch<A> = (value: A) => void;
  type SetStateAction<S> = S | ((prevState: S) => S);

[mweststrate]

🎉 This issue has been resolved in version 9.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀