我刚刚开始熟悉redux和redux-thunk，我尝试了下面的代码片段来处理async调用，使用redux和redux-thunk。

const redux = require('redux');
const thunk = require('redux-thunk').default;
const axios = require('axios');

const createStore = redux.createStore;
const applyMiddleware = redux.applyMiddleware;
const accessPoint = axios.create({
    baseURL: 'https://jsonplaceholder.typicode.com/',
    responseType: 'json',
    headers: {
        'Accept-Encoding': '',
    },
});

const FETCH_USER_PENDING = 'FETCH_USER_PENDING';
const FETCH_USER_FULFILLED = 'FETCH_USER_FULFILLED';
const FETCH_USER_REJECTED = 'FETCH_USER_REJECTED';

const initialState = {
    isLoading: false,
    users: [],
    error: '',
}

const fetchUserPending = () => {
    return {type: FETCH_USER_PENDING}
}
const fetchUserFulfilled = data => {
    return {type: FETCH_USER_FULFILLED, payload: data}
}
const fetchUserRejected = errorMessage => {
    return {type: FETCH_USER_REJECTED, payload: errorMessage}
}

const reducer = (state = initialState, action) => {
    const {type, payload} = action;
    switch(type){
        case FETCH_USER_PENDING: {
            return {
                ...state,
                isLoading: true,
            }
        }
        case FETCH_USER_FULFILLED: {
            return {
                isLoading: false,
                users: payload,
                error: ''
            }
        }
        case FETCH_USER_REJECTED: {
            return {
                isLoading: false,
                users: [],
                error: payload
            }
        }
        default: return state;
    }
}

const fetchUsers = () => {
    return function(dispatch){
        dispatch(fetchUserPending());
        accessPoint.get('users')
            .then(response => {
                dispatch(fetchUserFulfilled(response.data.map(user => user.name)))
            })
            .catch(error => {
                dispatch(fetchUserRejected(error.message));
            })
    }
}

const store = createStore(reducer, applyMiddleware(thunk));
store.subscribe(() => {
    console.log(store.getState());
})

store.dispatch(fetchUsers());

Code On CodeSandBox
这绝对可以正常工作，并提供预期的输出。
还尝试了相同的示例，但没有thunk和一些更改，

const redux = require('redux');
const axios = require('axios');

const createStore = redux.createStore;
const accessPoint = axios.create({
    baseURL: 'https://jsonplaceholder.typicode.com/',
    responseType: 'json',
    headers: {
        'Accept-Encoding': '',
    },
});

const FETCH_USER_PENDING = 'FETCH_USER_PENDING';
const FETCH_USER_FULFILLED = 'FETCH_USER_FULFILLED';
const FETCH_USER_REJECTED = 'FETCH_USER_REJECTED';

const initialState = {
    isLoading: false,
    users: [],
    error: '',
}

const fetchUserPending = () => {
    return {type: FETCH_USER_PENDING}
}
const fetchUserFulfilled = data => {
    return {type: FETCH_USER_FULFILLED, payload: data}
}
const fetchUserRejected = errorMessage => {
    return {type: FETCH_USER_REJECTED, payload: errorMessage}
}

const reducer = (state = initialState, action) => {
    const {type, payload} = action;
    switch(type){
        case FETCH_USER_PENDING: {
            return {
                ...state,
                isLoading: true,
            }
        }
        case FETCH_USER_FULFILLED: {
            return {
                isLoading: false,
                users: payload,
                error: ''
            }
        }
        case FETCH_USER_REJECTED: {
            return {
                isLoading: false,
                users: [],
                error: payload
            }
        }
        default: return state;
    }
}

const fetchUsers = (dispatch) => {
    dispatch(fetchUserPending());
    accessPoint.get('users')
        .then(response => {
            dispatch(fetchUserFulfilled(response.data.map(user => user.name)))
        })
        .catch(error => {
            dispatch(fetchUserRejected(error.message));
        })
}

const store = createStore(reducer);
store.subscribe(() => {
    console.log(store.getState());
})

fetchUsers(store.dispatch);

Code On CodeSandBox
这里我没有用react-thunk将函数传递给store.dispatch()，而是将store.dispatch传递给fetchUsers()函数，并且根据阶段的不同，我会向它分派动作。
当两个代码段（一个使用redux-thunk，另一个不使用）产生完全相同的输出时（不是总体差异，而是在上述场景中），redux-thunk会给异步调用带来混乱。
如果在实践这些代码时出现了问题，请改正。
提前感谢您的意见。