Reactjs：渲染没有返回任何内容

Question

我已经使用 create-react-app 设置了一个基本的 React 应用程序并创建了我的第一个组件。但是，由于浏览器中出现此错误，项目无法构建或呈现 window:

CountDown(...): Nothing was returned from render. This usually means a return statement is missing. Or, to render nothing, return null.
./src/index.js
D:/ReactDev/CountDownReact/countdown/src/index.js:8

这是我的 index.js 文件代码：

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import Bulma from 'bulma/css/bulma.css'
import App from './components/App/App';
import registerServiceWorker from './registerServiceWorker';

ReactDOM.render(<App />, document.getElementById('root'));
registerServiceWorker();

和我导入新组件的 App.js：

import React, {Component} from 'react';
import './App.css';
import CountDown from '../countdown/Countdown';

class App extends Component {
    render() {
        return(
            <div className="App">
                Hello React
                <CountDown/>
            </div>
        );
    }
}

export default App;

最后，我的Countdown组件代码：

import React from 'react';

const CountDown = (props) => {
    <section class="section">
        <div className="hero-body">
            <div class="container">
                <h1 class="title">Section</h1>
                <h2 class="subtitle">
                 A simple container to divide your page into <strong>sections</strong>, like the one you're currently
                reading
                </h2>
            </div>
        </div>
    </section>
};
export default CountDown;

我还需要在这里导入我的新组件吗？我该如何解决这个问题。谢谢。

Answer 1

您的倒计时组件 return 没有任何内容，您可以将 {} 替换为 () 以便获得 return.

import React from 'react';

const CountDown = (props) => (
    <section class="section">
        <div className="hero-body">
            <div class="container">
                <h1 class="title">Section</h1>
                <h2 class="subtitle">
                 A simple container to divide your page into <strong>sections</strong>, like the one you're currently
                reading
                </h2>
            </div>
        </div>
    </section>
);
export default CountDown;

应该可以了。

Answer 2

CountDown 组件没有 return JSX。您可以为 returning JSX 添加显式 return 语句。

Answer 3

遇到同样的问题：

function Input(props) {
return 
<input type={props.type} placeholder={props.placeholder} />
 }

相反，它必须是：

function Input(props) {
return <input type={props.type} placeholder={props.placeholder} />
 }

Reactjs：渲染没有返回任何内容

Reactjs: Nothing Was Returned From Render

reactjs

react-dom