从帖子中获取数据后无法将数据分配给状态？

Question

我试图将action.payload分配给状态记录的用户，但是当我在控制台日志中打印记录的用户时，它返回未定义的状态。

这是action.payload数据：

{
    id: 1, 
    firstname: "Leanne", 
    lastname: "Gram", 
    password: "123", 
    phone: "9474211442"
}

action.payload的数据类型为： 对象 ，如果将其更改为字符串，则输出保持不变。

这是console.log（this.state.loggeduser）的输出：

{}

---

handleSubmit = (dispatch, e) => {
    const firstname = this.state.Firstname;
    const password = this.state.password;
    const datas = {
        firstname, password                  //
    }

    alert(this.state.Firstname)
    e.preventDefault();
    axios.post('http://localhost:3001/login', datas).then(response => dispatch({
            type: 'ADD_DETAILS',
            payload: (response.data[0])
        })
    )
}

import React, {Component} from 'react'
import axios from 'axios'

const Context = React.createContext();
const reducer = (state, action) => {
    console.log("From switch")
    console.log(action.payload)
    switch (action.type) {
        case 'ADD_DETAIL':
            return {
                ...state,
                Loggeduser: [action.payload, ...state.Loggeduser]

            };
        default:
            return state;
    }
}

export class Provider extends Component {
    state = {
        posts: [],
        Loggeduser: [
            {}
        ],
        dispatch: action => this.setState(state => reducer(state, action))
    };

    render() {
        return (
            < Context.Provider
        value = {this.state} >
            {console.log("From main")}
        {
            console.log(this.state.Loggeduser)
        }

        {
            this.props.children
        }
    <
        /Context.Provider>
    )
    }
}

export const Consumer = Context.Consumer;