Warning 해결! React17->React18 [ReactDOM.render is no longer supported in React 18. Use createRoot instead. Until you switch to the new API, your app will behave as if it's running React 17]

index.js

import ReactDOM from "react-dom";

React 17 version ReactDom
위 코드를 삭제 후

import {createRoot} from 'react-dom/client';

삽입해준 후

const root = createRoot(document.getElementById('root'))

ReactDOM.render(

<React.StrictMode>

<App />

</React.StrictMode>,

document.getElementById("root")

);

여기서 ReactDom.render 부분을

root.render(

변경해준 후 document.getElementById("root") 를 제거해주면된다.

 

root.render(

<React.StrictMode>

<App />

</React.StrictMode>,

);

결과.

 

웹에서 개발자 도구를 확인해보자.