index.js

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import './index.css';  
import test from './Component/test';

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

正确的 app.js

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

export default App;

错误的test.js

import React, { Component } from 'react'; 
import logo from '../logo.svg';
 
require('../App.css'); 
class App1 extends Component {
  render() {
    return (
      <p className="App">
        <p className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h2>Welcome to React</h2>
        </p>
        <p className="App-intro">
          To get started, edit <code>src/App.js</code> and save to reload.
        </p> 
      </p>
    );
  }
}

export default App1;

都引入index.js test的 不能渲染 提示 warning 'test' is defined but never used no-unused-vars

help