Сделали useReducer для счетчика

src/App.jsx

@@ -1,108 +1,50 @@
-import React from 'react'
+import { useState, useReducer } from 'react'
 
-class MyComponent extends React.Component {
+function counterReducer(state, action) {
-    constructor(props) {
+    switch (action.type) {
-        super(props);
+        case 'increment':
-        this.state = { data: null };
+            return state + 1
-        this.handleClick = this.handleClick.bind(this);
+        case 'decrement':
-    }
+            return state - 1
-    
+        case 'reset':
-    render() {
+            return 0
-        return (
+        case 'set_value':
-            <div>
+            return action.value
-            {this.state.data ? (
+        default:
-                    <div>Данные: {this.state.data}</div>
+            return state
-                ) : (
-                    <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 Counter() {
-    controller = new AbortController()
+    const [count, dispatch] = useReducer(counterReducer,0);
     
-    componentDidMount() {
+    return (
-        fetch('https://api.example.com/data',{ singnal: this.controller.signal })
+        <div>
-        .then(responce => responce.json())
+            <span>Счетчик: {count}</span>
-        .then(json => this.setState({data: json}))
+            <button onClick={()=> dispatch({type: 'increment'})}>+</button>
-        .catch(error => {
+            <button onClick={()=> dispatch({type: 'decrement'})}>-</button>
-            if(error.name == 'AbortError') {
+            <button onClick={()=> dispatch({type: 'reset'})}>reset</button>
-                console.log('Aborted');
+            <button onClick={()=> dispatch({type: 'set_value', value: 5})}>set 5</button>
-            } else {
+        </div>
-                console.log('Other error',error);
+    )
-            }
-        });
-    }
-
-    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');
-        }
-    }
-}
-
-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);
+    const [tasks, setTasks] = useState([])
+    const [filter, setFilter] = useState('all')
+    const [sortBy,setSortBy] = useState('date')
+    
+    const addTask = newTask => {
+        setTasks([...tasks,newTask])
+    }
+    
+    
     
 	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 />}
+            <Counter />
 		</>
 	)
 }

src/App.module.scss

@@ -0,0 +1,15 @@
+.container {
+/*    display: flex;
+    flex-direction: column;
+    flex-wrap: nowrap;*/
+    height: 500px;
+    overflow: auto;
+    border: 1px solid black;
+}
+.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>
 )