Я уже не помню что там было

src/App.jsx

@@ -1,60 +1,79 @@
-import { memo, useState, useMemo } from 'react'
+import { useState, createContext, useContext } from 'react'
+import styles from './App.module.scss'
 
-function memoize(fn) {
-    const cache = new Map();
-    return function(...args) {
-        const key = JSON.stringify(args);
-        if (cache.has(key)) {
-            return cache.get(key);
-        }
-        const result = fn.apply(this, args);
-        cache.set(key,result);
-        return result;
-    }
-}
+const UserContext = createContext('')
 
-function fibonachi(n, memo={}) {
-    if (n in memo) {console.log(n);return memo[n];}
-    if (n <= 1) return 1;
-    memo[n] = fibonachi(n-1, memo) + fibonachi(n - 2, memo);
-    return memo[n];
-}
-
-const MyComponent = ({ value }) => {
-    console.log('Rendring');
-    return <div>{value}</div>
-}
-
-const MemoizedComponent = memo(MyComponent);
-
-const Child = memo(({ children }) => {
-    console.log('Child component rendred');
-    return <div>{children}</div>;
-});
-
-const Parent = () => {
-    const [count,setCount] = useState(0);
-    const [text, setText] = useState('');
+function UserProvider({ children }) {
+    const [name,setName] = useState('');
     
-    const stableChild = useMemo(() => <span>Memo text</span>,[]);
+    const toggleName = (newName) => {
+        setName(newName);
+    }
     
     return (
-        <>
-            <Child>
-                {stableChild}
-            </Child>
-            <input type="text" onChange={(e) => setText(e.target.value)} value={text} />
-            <button onClick={() => setCount(count + 1)}>Increment {count}</button>
-        </>
+        <UserContext.Provider value={{name, toggleName}}>
+            {children}
+        </UserContext.Provider>
     )
 }
 
-function App() {
+function Form() {
+    const {name, toggleName} = useContext(UserContext)
+    const [newName,setNewName] = useState('');
+    const handleSubmit = (event) => {
+        event.preventDefault();
+        toggleName(event.target[0].value)
+    }
+    const handlerChange = (event) => {
+        setNewName(event.target.value);
+    }
+    return (
+        <form onSubmit={handleSubmit}>
+        <input type='text' value={newName} onChange={handlerChange} />
+        <button type='submit'>Войти</button>
+        </form>
+    )
+}
+
+function ExitButton() {
+    const {name, toggleName} = useContext(UserContext)
+    
+    return (
+        <button onClick={() => toggleName('')}>Выход</button>
+    )
+}
+
+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 (
 		<>
+			{/* Добавьте тестовый контент для проверки */}
 			<h1>Hello, React!</h1>
-            <Parent />
-        </>
+        <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>
 )