Я уже не помню что там было

src/App.jsx

@@ -1,96 +1,78 @@
-import React from 'react'
+import { useState, createContext, useContext } from 'react'
 import styles from './App.module.scss'
 
-class Clock extends React.Component {
+const UserContext = createContext('')
-    constructor(props) {
+
-        super(props);
+function UserProvider({ children }) {
-        this.state = { date: new Date() };
+    const [name,setName] = useState('');
-    }
+    
-    componentDidMount() {
+    const toggleName = (newName) => {
-        this.timerId = setInterval( () => this.tick(), 1000);
+        setName(newName);
-    }
-    componentWillUnmount() {
-        clearInterval(this.timerId)
-    }
-    tick() {
-        this.setState({ date: new Date() })
-    }
-    render() {
-        return <div>{this.state.date.toLocaleTimeString()}</div>
     }
+    
+    return (
+        <UserContext.Provider value={{name, toggleName}}>
+            {children}
+        </UserContext.Provider>
+    )
 }
 
-function Clock2() {
+function Form() {
-    const [date, setDate] = React.useState(new Date());
+    const {name, toggleName} = useContext(UserContext)
-    
+    const [newName,setNewName] = useState('');
-    React.useEffect(()=>{
+    const handleSubmit = (event) => {
-        const timerId = setInterval(()=> setDate(new Date()),1000);
+        event.preventDefault();
-        return () => clearInterval(timerId);
+        toggleName(event.target[0].value)
-    },[])
+    }
-    
+    const handlerChange = (event) => {
-    return <div>{date.toLocaleTimeString()}</div>
+        setNewName(event.target.value);
+    }
+    return (
+        <form onSubmit={handleSubmit}>
+        <input type='text' value={newName} onChange={handlerChange} />
+        <button type='submit'>Войти</button>
+        </form>
+    )
 }
 
-function MouseTracker() {
+function ExitButton() {
-    const [x,setX] = React.useState(0);
+    const {name, toggleName} = useContext(UserContext)
-    const [y,setY] = React.useState(0);
     
-    const mouseMoveHandler = event => {
+    return (
-        setX(event.clientX);
+        <button onClick={() => toggleName('')}>Выход</button>
-        setY(event.clientY);
+    )
-    }
+}
-    
+
-    React.useEffect(()=>{
+function Toolbar() {
-        document.addEventListener('mousemove', mouseMoveHandler);
+    const {name, toggleName} = useContext(UserContext)
-        return () => {
+    return(
-            document.removeEventListener('mousemove',mouseMoveHandler);
+        <div className={styles.container}>
-        }
+            <h3>Панель пользователя</h3>
-    },[]);
+            {name && `Привет ${name}`}
-    
+            {name ? <ExitButton /> : <Form /> }
-    return <div className={styles.container}>
+            
-        <p>Координаты мыши:<br /> X:<b>{x}</b>, Y:<b>{y}</b></p>
         </div>
+    )
 }
 
-function DataFetcher() {
+function Page() {
-    const [posts,setPosts] = React.useState([]);
+    return (
-    const [users,setUsers] = React.useState([]);
+        <div>
-    
+            <h1 style={{textAlign: 'center'}}>Главная страница</h1>
-    const getPosts = async () => {
+            <Toolbar />
-        const response = await fetch('https://jsonplaceholder.typicode.com/posts');
+        </div>
-        const data = await response.json();
+    )
-        setUsers(data.reduce((acc, value) => {
-            if (!(value.userId in acc))
-                return [...acc,value.userId]
-            return acc
-        }))
-        console.log(users);
-        setPosts(data.slice(1,10));
-        
-    }
-    
-    React.useEffect(() => {
-        console.log("Компонент создан");
-        getPosts();
-        return () => {console.log("Компонент удален");setPosts([])};
-    },[])
-    
-    return <div><ol>{posts.map(post => <li id={post.id}>{post.title}</li>)}</ol></div>
 }
 
-function App() {
+function App() {    
-    const [tracker,setTracker] = React.useState(false);
-    const [dataFetcher,setDataFetcher] = React.useState(false);
     
 	return (
 		<>
+			{/* Добавьте тестовый контент для проверки */}
 			<h1>Hello, React!</h1>
-            <Clock />
+        <UserProvider>
-            <Clock2 />
+            <Page />
-            <button onClick={() => setTracker(!tracker)}>Показать/Скрыть трекер</button>
+        </UserProvider>
-            { tracker && <MouseTracker /> }
-            <button onClick={() => setDataFetcher(!dataFetcher)}>Показать/Скрыть посты</button>
-            { dataFetcher && <DataFetcher /> }
 		</>
 	)
 }

src/App.module.scss

@@ -1,11 +1,13 @@
 .container {
-    width: 300px;
+    height: 500px;
-    height: 200px;
+    border: 1px solid black;
-    border: 2px dashed grey;
+    border-radius: 10px;
-    margin: 10px;
+    background-color: lightblue;
-    text-align: center;
-    p {
-        margin-top: 20%;
-    }
 }
-
+.item {
+    font-size: 16pt;
+    border: 1px dotted gray;
+    /*margin: 5px 10px;
+    padding: 10px;*/
+    border-radius: 5px;
+}