Сделали таймер

src/App.jsx

@@ -1,50 +1,108 @@
-import { useState, useReducer } from 'react'
+import React from 'react'
 
-function counterReducer(state, action) {
-    switch (action.type) {
-        case 'increment':
-            return state + 1
-        case 'decrement':
-            return state - 1
-        case 'reset':
-            return 0
-        case 'set_value':
-            return action.value
-        default:
-            return state
-    }
+class MyComponent extends React.Component {
+    constructor(props) {
+        super(props);
+        this.state = { data: null };
+        this.handleClick = this.handleClick.bind(this);
     }
     
-function Counter() {
-    const [count, dispatch] = useReducer(counterReducer,0);
-    
+    render() {
         return (
             <div>
-            <span>Счетчик: {count}</span>
-            <button onClick={()=> dispatch({type: 'increment'})}>+</button>
-            <button onClick={()=> dispatch({type: 'decrement'})}>-</button>
-            <button onClick={()=> dispatch({type: 'reset'})}>reset</button>
-            <button onClick={()=> dispatch({type: 'set_value', value: 5})}>set 5</button>
+            {this.state.data ? (
+                    <div>Данные: {this.state.data}</div>
+                ) : (
+                    <div>Загрузка...</div>
+                )}
+                <button onClick={this.handleClick}>Обновить</button>
             </div>
         )
     }
     
-function App() {
-    const [tasks, setTasks] = useState([])
-    const [filter, setFilter] = useState('all')
-    const [sortBy,setSortBy] = useState('date')
+    componentDidMount() {
+        fetch('https://api.example.com/data')
+        .then(responce => responce.json())
+        .then(json => this.setState({data: json}));
         
-    const addTask = newTask => {
-        setTasks([...tasks,newTask])
+        this.timerId = setInterval(()=> console.log('Tick'), 1000);
     }
     
+    componentWillUnmout() {
+        clearInterval(this.timerId);
+    }
     
+    handleClick() {
+        this.setState({data: 'Данные'})
+    }
+}
+
+class MyComponent2 extends React.Component {
+    controller = new AbortController()
+
+    componentDidMount() {
+        fetch('https://api.example.com/data',{ singnal: this.controller.signal })
+        .then(responce => responce.json())
+        .then(json => this.setState({data: json}))
+        .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() {
+        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);
     
 	return (
 		<>
-			{/* Добавьте тестовый контент для проверки */}
-			<h1>Hello, React!</h1>
-            <Counter />
+			<h1>Таймер с классом</h1>
+            <button onClick={()=>setShow(prev => !prev)}>{show ? 'Скрыть' : 'Показать'} таймер</button>
+            {show && <Timer />}
 		</>
 	)
 }

src/App.module.scss

@@ -1,15 +0,0 @@
-.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

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