reactjs - React.Children.only 期望收到单个 React 元素子错误

Question

我收到“React.Children.only 希望收到单个 React 元素子元素。”从下面的代码。

我使用create-react-app创建了一个新的react应用程序，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。

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'));

Answer 1

您这里有一个空间:

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

JSX 对单行间距有点挑剔。上面的内容基本上被解释为:

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

(事实上， Prettier 将产生 pretty much this exact output )

您可以删除空格:

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

或者将其分成多行:

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