install react application

   2 npm -v

   3 npm uninstall -g create-react-app

   4 npm cache clean --force

   5 npm init react-app my-react-app

cd my-react-app

npm start

how to view

React Directly in HTML

The quickest way start learning React is to write React directly in your HTML files.

on ist initial 

app.js

it will look like thsi 

import logo from './logo.svg';

import './App.css';

function App() {

  return (

    <div className="App">

      <header className="App-header">

        <img src={logo} className="App-logo" alt="logo" />

        <p>

          Edit <code>src/App.js</code> and save to reload.

        </p>

        <a

          className="App-link"

          href="https://reactjs.org"

          target="_blank"

          rel="noopener noreferrer"

        >

          Learn React

        </a>

      </header>

    </div>

  );

}

export default App;

modify the app.js

import './App.css';

function App() {

  return (

    <div className="App">

      <h1>Hello World!</h1>

    </div>

  );

}

export default App;

=