React.Children.only 预计会收到单个 React 元素子错误 [英] React.Children.only expected to receive a single React element child error

问题描述

我收到React.Children.only 预计会收到一个 React 元素孩子."从下面的代码.

我使用 create-react-app 创建了一个新的 React 应用，并安装了 redux 和 react-redux，并创建了一个简单的 reducer 并用它创建了 store.

从react"导入React；从react-dom"导入 ReactDOM；import { createStore, combineReducers } from "redux";从react-redux"导入{提供者}；从'./logo.svg'导入标志；导入'./App.css';类 App 扩展了 React.Component {使成为() {返回 (<div className="应用程序"><div className="App-header"><img src={logo} className="App-logo" alt="logo"/><h2>欢迎反应</h2>

<p className="App-intro">首先，编辑 src/App.js;并保存以重新加载.</p>

);}}函数 productReducer(state = [], action) {返回状态；}常量存储 = 创建存储(productReducer);ReactDOM.render((<Provider store={store}><App/> </Provider>), document.getElementById('root'));

解决方案

您在这里有一个空间:

 ↓<Provider store={store}><App/></提供者>

JSX 对单行的间距有点挑剔.以上基本上被解释为:

{' '}

(实际上，Prettier 会产生 几乎此确切输出)

您可以删除空格:

或者把它分成多行:

<应用程序/></提供者>

I'm getting 'React.Children.only expected to receive a single React element child.' from the following code.

I have created a new react app using create-react-app and installed redux and react-redux, and created a simple reducer and creating store with that.

import React from "react";
import ReactDOM from "react-dom";
import { createStore, combineReducers } from "redux";
import { Provider } from "react-redux";

import logo from './logo.svg';
import './App.css';

class App extends React.Component {
  render() {
    return (
      <div className="App">
        <div className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h2>Welcome to React</h2>
        </div>
        <p className="App-intro">
          To get started, edit <code>src/App.js</code> and save to reload.
        </p>
      </div>
    );
  }
}


function productReducer(state = [], action) {
  return state;
}

const store = createStore(
  productReducer
);

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

解决方案

You have a space here:

                               ↓
<Provider store={store}><App /> </Provider>

JSX is kinda picky about spacing on single lines. The above essentially gets interpreted as:

<Provider store={store}><App />{' '}</Provider>

(In fact, Prettier will produce pretty much this exact output)

You can either remove the space:

<Provider store={store}><App /></Provider>

Or break it up on to multiple lines:

<Provider store={store}>
    <App />
</Provider>

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