react-1

安装：

npm install create-react-app -g

create-ract-app my-project

组件：

组件welcom.js

import React from 'react';

class welcome extends React.Component{
    
    render() {
        const array = ['tom', 'john', 'daming']
        return (
            <div>
                <h1>Hello World</h1>
                <ul>
                    {
                        array.map(item => 
                        <li>{item}</li>
                        )
                    }
                </ul>
            </div>
        )
            
    }
}

export default welcome

使用组件：

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import reportWebVitals from './reportWebVitals';
import Welcome from './welcome.js'

ReactDOM.render(
  <React.StrictMode>
    <Welcome />
  </React.StrictMode>,
  document.getElementById('root')
);

// If you want to start measuring performance in your app, pass a function
// to log results (for example: reportWebVitals(console.log))
// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
reportWebVitals();