Update chapter 2

Author: velopert

02/hello-react/package.json

@@ -3,9 +3,9 @@
   "version": "0.1.0",
   "private": true,
   "dependencies": {
-    "react": "^16.8.6",
-    "react-dom": "^16.8.6",
-    "react-scripts": "3.0.0"
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0",
+    "react-scripts": "^5.0.1"
   },
   "scripts": {
     "start": "react-scripts start",

02/hello-react/src/index.js

@@ -1,12 +1,12 @@
 import React from 'react';
-import ReactDOM from 'react-dom';
+import ReactDOM from 'react-dom/client';
 import './index.css';
 import App from './App';
-import * as serviceWorker from './serviceWorker';
 
-ReactDOM.render(<App />, document.getElementById('root'));
+const root = ReactDOM.createRoot(document.getElementById('root'));
 
-// If you want your app to work offline and load faster, you can change
-// unregister() to register() below. Note this comes with some pitfalls.
-// Learn more about service workers: https://bit.ly/CRA-PWA
-serviceWorker.unregister();
+root.render(
+  <React.StrictMode>
+    <App />
+  </React.StrictMode>
+);