Сделали таймер

src/App.jsx

@@ -1,44 +1,108 @@
-import { useMutation, QueryClientProvider, QueryClient } from '@tanstack/react-query'
-import PostAddForm from './components/PostAddForm'
+import React from 'react'
 
-/*
-const mutation = useMutation({
-    mutationFn: newUser => {
-        fetch('https://jsonplaceholder.typicode.com/users', {
-            method: 'GET',
-            headers: {'Content-type':'application/json'},
-            body: JSON.stringify(newUser),
-        }).then(res => res.json())
+class MyComponent extends React.Component {
+    constructor(props) {
+        super(props);
+        this.state = { data: null };
+        this.handleClick = this.handleClick.bind(this);
     }
-})
-*/
+    
+    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'})
+    }
+}
 
-const createQueryClient = () => {
-    new QueryClient({
-        defaultOptions: {
-            queries: {
-                staleTime: 5 * 60*1000,
-                retry: 1,
-                gcTime: 10*60*1000,
-                refetchOnWindowFocus: false,
-            },
-            mutations: {
-                retry:0,
-                onError: error => {console.error('Mutation error:',error.message)}
+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>
-        <QueryClientProvider client={createQueryClient}>
-            <PostAddForm />
-        </QueryClientProvider>
-            
+			<h1>Таймер с классом</h1>
+            <button onClick={()=>setShow(prev => !prev)}>{show ? 'Скрыть' : 'Показать'} таймер</button>
+            {show && <Timer />}
 		</>
 	)
 }

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>
 )