How to use Redux-Thunk with Redux Toolkit's createSlice?

I have come across Redux Toolkit (RTK) and wanting to implement further functionality it provides. My application dispatches to reducers slices created via the createSlice({}) (see createSlice api docs)

This so far works brilliantly. I can easily use the built in dispatch(action) and useSelector(selector) to dispatch the actions and receive/react to the state changes well in my components.

I would like to use an async call from axios to fetch data from the API and update the store as the request is A) started B) completed.

I have seen redux-thunk and it seems as though it is designed entirely for this purpose, but the new RTK does not seem to support it within a createSlice() following general googling.

Is the above the current state of implementing thunk with slices?

I have seen in the docs that you can add extraReducers to the slice but unsure if this means I could create more traditional reducers that use thunk and have the slice implement them?

Overall, it is misleading as the RTK docs show you can use thunk, but doesn't seem to mention it not being accessible via the new slices api.

Example from Redux Tool Kit Middleware

const store = configureStore({
  reducer: rootReducer,
  middleware: [thunk, logger]
})

My code for a slice showing where an async call would fail and some other example reducers that do work.

import { getAxiosInstance } from '../../conf/index';

export const slice = createSlice({
    name: 'bundles',
    initialState: {
        bundles: [],
        selectedBundle: null,
        page: {
            page: 0,
            totalElements: 0,
            size: 20,
            totalPages: 0
        },
        myAsyncResponse: null
    },

    reducers: {
        //Update the state with the new bundles and the Spring Page object.
        recievedBundlesFromAPI: (state, bundles) => {
            console.log('Getting bundles...');
            const springPage = bundles.payload.pageable;
            state.bundles = bundles.payload.content;
            state.page = {
                page: springPage.pageNumber,
                size: springPage.pageSize,
                totalElements: bundles.payload.totalElements,
                totalPages: bundles.payload.totalPages
            };
        },

        //The Bundle selected by the user.
        setSelectedBundle: (state, bundle) => {
            console.log(`Selected ${bundle} `);
            state.selectedBundle = bundle;
        },

        //I WANT TO USE / DO AN ASYNC FUNCTION HERE...THIS FAILS.
        myAsyncInSlice: (state) => {
            getAxiosInstance()
                .get('/')
                .then((ok) => {
                    state.myAsyncResponse = ok.data;
                })
                .catch((err) => {
                    state.myAsyncResponse = 'ERROR';
                });
        }
    }
});

export const selectBundles = (state) => state.bundles.bundles;
export const selectedBundle = (state) => state.bundles.selectBundle;
export const selectPage = (state) => state.bundles.page;
export const { recievedBundlesFromAPI, setSelectedBundle, myAsyncInSlice } = slice.actions;
export default slice.reducer;

My store setup (store config).

import { configureStore } from '@reduxjs/toolkit';
import thunk from 'redux-thunk';

import bundlesReducer from '../slices/bundles-slice';
import servicesReducer from '../slices/services-slice';
import menuReducer from '../slices/menu-slice';
import mySliceReducer from '../slices/my-slice';

const store = configureStore({
    reducer: {
        bundles: bundlesReducer,
        services: servicesReducer,
        menu: menuReducer,
        redirect: mySliceReducer
    }
});
export default store;

I'm a Redux maintainer and creator of Redux Toolkit.

FWIW, nothing about making async calls with Redux changes with Redux Toolkit.

You'd still use an async middleware (typically redux-thunk), fetch data, and dispatch actions with the results.

As of Redux Toolkit 1.3, we do have a helper method called createAsyncThunk that generates the action creators and does request lifecycle action dispatching for you, but it's still the same standard process.

This sample code from the docs sums up the usage;

import { createAsyncThunk, createSlice } from '@reduxjs/toolkit'
import { userAPI } from './userAPI'

// First, create the thunk
const fetchUserById = createAsyncThunk(
  'users/fetchByIdStatus',
  async (userId, thunkAPI) => {
    const response = await userAPI.fetchById(userId)
    return response.data
  }
)

// Then, handle actions in your reducers:
const usersSlice = createSlice({
  name: 'users',
  initialState: { entities: [], loading: 'idle' },
  reducers: {
    // standard reducer logic, with auto-generated action types per reducer
  },
  extraReducers: (builder) => {
    // Add reducers for additional action types here, and handle loading state as needed
    builder.addCase(fetchUserById.fulfilled, (state, action) => {
      // Add user to the state array
      state.entities.push(action.payload)
    })
  },
})

// Later, dispatch the thunk as needed in the app
dispatch(fetchUserById(123))

See the Redux Toolkit "Usage Guide: Async Logic and Data Fetching" docs page for some additional info on this topic.

Hopefully that points you in the right direction!