错误：StateProvider(...)：渲染没有返回任何内容。 这通常意味着缺少 return 语句。 或者，什么也不渲染，返回 null

Question

我有这个错误作为错误：StateProvider（...）：没有从渲染返回。 这通常意味着缺少 return 语句。 或者，不渲染任何内容，返回 null 。 由于本节，它即将到来。 我正在处理我的项目并使用react和redux 。

 import React from 'react'; import ReactDOM from 'react-dom'; import './index.css'; import App from './App'; import { StateProvider } from './StateProvider'; import { reducer, initialState } from './reducer'; ReactDOM.render( <React.StrictMode> <StateProvider initialState={initialState} reducer={reducer}> <App /> </StateProvider> </React.StrictMode>, document.getElementById('root') );

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我的 App 组合是这样的

 import './App.css'; import Header from "./Header"; import Home from "./Home"; import Checkout from "./Checkout"; import {BrowserRouter as Router, Switch} from "react-router-dom"; function App() { return ( <Router> <div className="app"> <Header/> <Switch> <Router path="/checkout"> <Checkout/> </Router> <Router path="/"> <Home/> </Router> </Switch> </div> </Router> ); } export default App;

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而我的减速机是这样的

 const initialState = { basket: [], }; const reducer = (state, action) => { switch(action.type){ case "ADD_TO_BASKET": return{...state, basket: [...state, action.item], }; default: return state; } }; export {reducer, initialState};

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而我的 stateProvider 是这样的

 import React, { createContext, useContext, useReducer } from "react"; export const StateContext = createContext(); export const StateProvider = ({ reducer, initialState, children}) => { <StateContext.Provider value={useReducer(reducer, initialState)}> {children} </StateContext.Provider> }; export const useStateValue = () => useContext(StateContext);

Answer 1

您在这里缺少 return 声明：

export const StateProvider = ({ reducer, initialState, children}) => {
     
    return (<StateContext.Provider value={useReducer(reducer, initialState)}>
        {children}
    </StateContext.Provider>)
};

Answer 2

对我来说，一旦我在里面绑定，什么也不会显示。 但也没有错误...

export const StateProvider = ({ reducer, initialState, children}) => {

return (<StateContext.Provider value={useReducer(reducer, initialState)}>
    {children}
</StateContext.Provider>)

};

不适合我......它不允许在 function 内返回（）