final

src/App.jsx

@@ -1,108 +1,45 @@
-import React from 'react'
+import React, { useMemo, useCallback, useState } from 'react'
 
-class MyComponent extends React.Component {
+const TodoItem = React.memo(({ item, onToggle, onDelete }) => {
-    constructor(props) {
+    console.log(`rendred ${item.id}`);
-        super(props);
+    return <li>
-        this.state = { data: null };
+            {item.name}
-        this.handleClick = this.handleClick.bind(this);
+            <button onClick={() => onToggle(item.id)}>Done</button>
-    }
+            <button onClick={() => onDelete(item.id)}>remove</button>
-    
+        </li>
-    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'})
-    }
-}
 
-class MyComponent2 extends React.Component {
+function ItemList({ items }) {
-    controller = new AbortController()
 
-    componentDidMount() {
+    const handleToggle = useCallback(id => {
-        fetch('https://api.example.com/data',{ singnal: this.controller.signal })
+        items.done = true;
-        .then(responce => responce.json())
+        console.log(`Item ${id} done`)
-        .then(json => this.setState({data: json}))
+        console.log(id)
-        .catch(error => {
+    },[]);
-            if(error.name == 'AbortError') {
-                console.log('Aborted');
-            } else {
-                console.log('Other error',error);
-            }
-        });
-    }
-
-    componentWillUnmount() {
-        this.controller.abort()
-    }
-}
-class MyComponent3 extends React.Component {
-    componentDidMount() {
-        this.loadData();
-    }
     
-    async loadData() {
+    const handleDelete = useCallback(id => {
-        try {
+        items.pop(id);
-            const response = await fetch('https://api.example.com/data');
+    },[]);
-            const data = await response.json();
+    return (
-            this.setSate({ data });
+        <>
-        } catch {
+            <h3>List items</h3>
-            console.log('error');
+            {items.map(item => (
-        }
+             <TodoItem key={item.id} item={item}
-    }
+              onToggle={handleToggle} onDelete={handleDelete} />
-}
+             ))}
-
+        </>
-class Timer extends React.Component {
+    )
-    constructor(props) {
-        super(props);
-        this.state = { seconds: 0 }
-    }
-    
-    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>
-    }
 }
 
 function App() {
-    const [show,setShow] = React.useState(true);
-    
 	return (
 		<>
-			<h1>Таймер с классом</h1>
+			{/* Добавьте тестовый контент для проверки */}
-            <button onClick={()=>setShow(prev => !prev)}>{show ? 'Скрыть' : 'Показать'} таймер</button>
+			<h1>Hello, React!</h1>
-            {show && <Timer />}
+            <ItemList items={[
+                {id:1,name:'Первый',done:false},
+                {id:2,name:'Второй',done:false}
+            ]} />
 		</>
 	)
 }