final

src/App.jsx

@@ -1,96 +1,45 @@
-import React from 'react'
+import React, { useMemo, useCallback, useState } from 'react'
-import styles from './App.module.scss'
 
-class Clock extends React.Component {
+const TodoItem = React.memo(({ item, onToggle, onDelete }) => {
-    constructor(props) {
+    console.log(`rendred ${item.id}`);
-        super(props);
+    return <li>
-        this.state = { date: new Date() };
+            {item.name}
-    }
+            <button onClick={() => onToggle(item.id)}>Done</button>
-    componentDidMount() {
+            <button onClick={() => onDelete(item.id)}>remove</button>
-        this.timerId = setInterval( () => this.tick(), 1000);
+        </li>
-    }
+})
-    componentWillUnmount() {
-        clearInterval(this.timerId)
-    }
-    tick() {
-        this.setState({ date: new Date() })
-    }
-    render() {
-        return <div>{this.state.date.toLocaleTimeString()}</div>
-    }
-}
 
-function Clock2() {
+function ItemList({ items }) {
-    const [date, setDate] = React.useState(new Date());
 
-    React.useEffect(()=>{
+    const handleToggle = useCallback(id => {
-        const timerId = setInterval(()=> setDate(new Date()),1000);
+        items.done = true;
-        return () => clearInterval(timerId);
+        console.log(`Item ${id} done`)
-    },[])
+        console.log(id)
-    
-    return <div>{date.toLocaleTimeString()}</div>
-}
-
-function MouseTracker() {
-    const [x,setX] = React.useState(0);
-    const [y,setY] = React.useState(0);
-    
-    const mouseMoveHandler = event => {
-        setX(event.clientX);
-        setY(event.clientY);
-    }
-    
-    React.useEffect(()=>{
-        document.addEventListener('mousemove', mouseMoveHandler);
-        return () => {
-            document.removeEventListener('mousemove',mouseMoveHandler);
-        }
     },[]);
     
-    return <div className={styles.container}>
+    const handleDelete = useCallback(id => {
-        <p>Координаты мыши:<br /> X:<b>{x}</b>, Y:<b>{y}</b></p>
+        items.pop(id);
-        </div>
+    },[]);
-}
+    return (
-
+        <>
-function DataFetcher() {
+            <h3>List items</h3>
-    const [posts,setPosts] = React.useState([]);
+            {items.map(item => (
-    const [users,setUsers] = React.useState([]);
+             <TodoItem key={item.id} item={item}
-    
+              onToggle={handleToggle} onDelete={handleDelete} />
-    const getPosts = async () => {
+             ))}
-        const response = await fetch('https://jsonplaceholder.typicode.com/posts');
+        </>
-        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() {
-    const [tracker,setTracker] = React.useState(false);
-    const [dataFetcher,setDataFetcher] = React.useState(false);
-    
 	return (
 		<>
+			{/* Добавьте тестовый контент для проверки */}
 			<h1>Hello, React!</h1>
-            <Clock />
+            <ItemList items={[
-            <Clock2 />
+                {id:1,name:'Первый',done:false},
-            <button onClick={() => setTracker(!tracker)}>Показать/Скрыть трекер</button>
+                {id:2,name:'Второй',done:false}
-            { tracker && <MouseTracker /> }
+            ]} />
-            <button onClick={() => setDataFetcher(!dataFetcher)}>Показать/Скрыть посты</button>
-            { dataFetcher && <DataFetcher /> }
 		</>
 	)
 }

src/App.module.scss

@@ -1,11 +0,0 @@
-.container {
-    width: 300px;
-    height: 200px;
-    border: 2px dashed grey;
-    margin: 10px;
-    text-align: center;
-    p {
-        margin-top: 20%;
-    }
-}
-

src/main.jsx

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