I am new to react

index.js

// import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import Card from './Card';
import 'tachyons';
import reportWebVitals from './reportWebVitals';

ReactDOM.render(
  <Card/>,
  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. 
reportWebVitals();

Card.js

// import React from "react";
const Card = ()=>{
    return(
        <div>
          <h1>I am A Card </h1>
        </div>
    );
}
   
export default Card;

as in both the file I commented // import React from 'react';

but <Card/>(in index.js) and <div><h1>I am A Card </h1></div> (in Card.js) which later turn into React.createElement(); function call

which requires React which I already commented so it should give me an error 'React' is not defined no-undef but I am not getting any error here why.