修复错误：操作必须是纯对象。相反，实际类型是："未定义"。您可能需要将中间件添加到商店设置

Question

我的错误消息：

"错误：操作必须是纯对象。实际类型为："undefined"。您可能需要在商店设置中添加中间件来处理调度其他值，例如"redux thunk"来处理调度功能。看见https://redux.js.org/tutorials/fundamentals/part-4-store#middleware和https://redux.js.org/tutorials/fundamentals/part-6-async-logic#using-以redux-thunk中间件为例">

我找到了很多关于这个错误的答案，但没有一个对我有帮助

我在我的react应用程序中存储了一些部件。最后一部分，提出错误。

我真的很困惑，按照所有的答案，我应该如何创建商店。

我的index.js文件：

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import reportWebVitals from './reportWebVitals';
import '../node_modules/video-react/dist/video-react.css'; // import css
import thunk from 'redux-thunk';
import { BrowserRouter } from 'react-router-dom';
import { Provider } from 'react-redux';
import { combineReducers,compose ,applyMiddleware,createStore } from 'redux';
import { file, user,school,student } from "./Utilities/store/reducers";
const combine = combineReducers(
{
filePart: file,
userPart: user,
schoolPart:school,
student:student
}
);


ReactDOM.render(<BrowserRouter>
<Provider store={createStore(combine, applyMiddleware(thunk))}>
<App />
</Provider>
</BrowserRouter>, document.getElementById('root'));

student.js减速器：

import {type} from './../functions/student'
import * as functions from './../functions/student'
const initilize = {
all: [],
schools:[],
courses:[]
};
export const student = (state = initilize, action) => {
switch (action.type) {
case type.get: return functions.getCurrent(state);
case type.fill: return functions.fill(state,action.payload);
}
return state;
}

student.js操作：

import * as functions from './../functions/student'
import { type } from './../functions/student'

export const getCurrent = () => {
return { type: type.get };
}
export const fill = (post) => {
return { type: type.fill, payload: post }
}

export const get = (students, teacherId) => {
if (students && students.all.length > 0) {
getCurrent();
}
if (students === undefined || students.all.length === 0) {
return async(dispatch) => {
let result = await functions.get(teacherId);
dispatch(fill(result));
}
}
else
getCurrent();
}

当我调用actionget((时会发生错误

Answer 1

如果(students === undefined || students.all.length === 0)不是true，则该方法不会返回任何内容。但你在某个地方dispatch(get(students, teacherId))，所以本质上你是dispatch(undefined)

让它总是返回一些东西：

export const get = (students, teacherId) => {
return async(dispatch) => {
if (students && students.all.length > 0) {
getCurrent();
}
if (students === undefined || students.all.length === 0) {
let result = await functions.get(teacherId);
dispatch(fill(result));
}
}
}
}