Actions aren't resolved with generic slice return types

[huwshimi]

When adding a return type to a generic createSlice function the action types are no longer resolved.

Here is the example from the docs with the return type added:

export const createGenericSlice = <
  T,
  Reducers extends SliceCaseReducers<GenericState<T>>
>({
  name = "",
  initialState,
  reducers,
}: {
  name: string;
  initialState: GenericState<T>;
  reducers: ValidateSliceCaseReducers<GenericState<T>, Reducers>;
}): Slice<GenericState<T>, Reducers, string> => { // Return type added here
  return createSlice({
    name,
    initialState,
    reducers: {
      start(state) {
        state.status = "loading";
      },
      /**
       * If you want to write to values of the state that depend on the generic
       * (in this case: `state.data`, which is T), you might need to specify the
       * State type manually here, as it defaults to `Draft<GenericState<T>>`,
       * which can sometimes be problematic with yet-unresolved generics.
       * This is a general problem when working with immer's Draft type and generics.
       */
      success(state: GenericState<T>, action: PayloadAction<T>) {
        state.data = action.payload;
        state.status = "finished";
      },
      ...reducers,
    },
  });
};

const wrappedSlice = createGenericSlice({
  name: "test",
  initialState: { status: "loading" } as GenericState<string>,
  reducers: {
    magic(state) {
      state.status = "finished";
      state.data = "hocus pocus";
    },
  },
});

const actions = wrappedSlice.actions;

actions.magic(); // Works fine
actions.start(); // Not found
actions.success(); // Not found

The start and success actions are not resolved: Property 'success' does not exist on type 'CaseReducerActions<{ magic(state: { data?: string; status: "loading" | "finished" | "error"; }): void; }>'..

Removing the return type allows the actions to resolve.

Am I providing the wrong return type or do I have to resolve the actions in another way?

Here is a playground with this code and errors.

I noticed createSlice is being updated, so maybe this issue will be resolved in the PR: #637.

[markerikson]

Out of curiosity, why are you trying to specify a return type there in the first place?

[huwshimi]

@markerikson we have @typescript-eslint/explicit-module-boundary-types turned on in our project.

So when I add export to createGenericSlice it complains about Missing return type on function. (@typescript-eslint/explicit-module-boundary-types)

[markerikson]

Well, that's why. Turn off that lint rule :)

If it compiles and runs fine without explicitly declaring a return type, then you don't need it here.

Lint rules are supposed to help you. If a lint rule doesn't "spark joy", turn it off :)

[huwshimi]

@markerikson hah, fair point. I might just do that :).

[phryneas]

Yeah, have to agree very strongly with Mark there. RTK enables you to write a lot less TS code, but when you start specifying it's types manually, you're in for a very bad time. I'd also suggest turning that rule off.

[huwshimi]

Thanks a lot @phryneas and @markerikson, I'll do without the rule.