Я уже не помню что там было

src/App.jsx

@@ -1,108 +1,78 @@
-import React from 'react'
+import { useState, createContext, useContext } from 'react'
+import styles from './App.module.scss'
 
-class MyComponent extends React.Component {
-    constructor(props) {
-        super(props);
-        this.state = { data: null };
-        this.handleClick = this.handleClick.bind(this);
+const UserContext = createContext('')
+
+function UserProvider({ children }) {
+    const [name,setName] = useState('');
+    
+    const toggleName = (newName) => {
+        setName(newName);
     }
     
-    render() {
-        return (
-            <div>
-            {this.state.data ? (
-                    <div>Данные: {this.state.data}</div>
-                ) : (
-                    <div>Загрузка...</div>
-                )}
-                <button onClick={this.handleClick}>Обновить</button>
-            </div>
-        )
-    }
-    
-    componentDidMount() {
-        fetch('https://api.example.com/data')
-        .then(responce => responce.json())
-        .then(json => this.setState({data: json}));
-        
-        this.timerId = setInterval(()=> console.log('Tick'), 1000);
-    }
-    
-    componentWillUnmout() {
-        clearInterval(this.timerId);
-    }
-    
-    handleClick() {
-        this.setState({data: 'Данные'})
-    }
+    return (
+        <UserContext.Provider value={{name, toggleName}}>
+            {children}
+        </UserContext.Provider>
+    )
 }
 
-class MyComponent2 extends React.Component {
-    controller = new AbortController()
-
-    componentDidMount() {
-        fetch('https://api.example.com/data',{ singnal: this.controller.signal })
-        .then(responce => responce.json())
-        .then(json => this.setState({data: json}))
-        .catch(error => {
-            if(error.name == 'AbortError') {
-                console.log('Aborted');
-            } else {
-                console.log('Other error',error);
-            }
-        });
+function Form() {
+    const {name, toggleName} = useContext(UserContext)
+    const [newName,setNewName] = useState('');
+    const handleSubmit = (event) => {
+        event.preventDefault();
+        toggleName(event.target[0].value)
     }
-
-    componentWillUnmount() {
-        this.controller.abort()
-    }
-}
-class MyComponent3 extends React.Component {
-    componentDidMount() {
-        this.loadData();
-    }
-    
-    async loadData() {
-        try {
-            const response = await fetch('https://api.example.com/data');
-            const data = await response.json();
-            this.setSate({ data });
-        } catch {
-            console.log('error');
-        }
+    const handlerChange = (event) => {
+        setNewName(event.target.value);
     }
+    return (
+        <form onSubmit={handleSubmit}>
+        <input type='text' value={newName} onChange={handlerChange} />
+        <button type='submit'>Войти</button>
+        </form>
+    )
 }
 
-class Timer extends React.Component {
-    constructor(props) {
-        super(props);
-        this.state = { seconds: 0 }
-    }
+function ExitButton() {
+    const {name, toggleName} = useContext(UserContext)
     
-    componentDidMount() {
-        console.log('Timer mounted');
-        this.interval = setInterval(()=>{
-            this.setState(prevState => ({seconds: prevState.seconds + 1}))
-        },1000);
-    }
-    
-    componentWillUnmount() {
-        console.log('Timer unmount');
-        clearInterval(this.interval);
-    }
-    render() {
-        return <h2>Прошло секунд: {this.state.seconds}</h2>
-    }
+    return (
+        <button onClick={() => toggleName('')}>Выход</button>
+    )
 }
 
-function App() {
-    const [show,setShow] = React.useState(true);
+function Toolbar() {
+    const {name, toggleName} = useContext(UserContext)
+    return(
+        <div className={styles.container}>
+            <h3>Панель пользователя</h3>
+            {name && `Привет ${name}`}
+            {name ? <ExitButton /> : <Form /> }
+            
+        </div>
+    )
+}
+
+function Page() {
+    return (
+        <div>
+            <h1 style={{textAlign: 'center'}}>Главная страница</h1>
+            <Toolbar />
+        </div>
+    )
+}
+
+function App() {    
     
 	return (
 		<>
-			<h1>Таймер с классом</h1>
-            <button onClick={()=>setShow(prev => !prev)}>{show ? 'Скрыть' : 'Показать'} таймер</button>
-            {show && <Timer />}
+			{/* Добавьте тестовый контент для проверки */}
+			<h1>Hello, React!</h1>
+        <UserProvider>
+            <Page />
+        </UserProvider>
 		</>
 	)
 }

src/App.module.scss

@@ -0,0 +1,13 @@
+.container {
+    height: 500px;
+    border: 1px solid black;
+    border-radius: 10px;
+    background-color: lightblue;
+}
+.item {
+    font-size: 16pt;
+    border: 1px dotted gray;
+    /*margin: 5px 10px;
+    padding: 10px;*/
+    border-radius: 5px;
+}

src/main.jsx

@@ -4,5 +4,7 @@ import { createRoot } from 'react-dom/client'
 import App from './App.jsx'
 
 createRoot(document.getElementById('root')).render(
+	<StrictMode>
 		<App />
+	</StrictMode>
 )