Сделали несколько кастомных хуков

package-lock.json

@@ -8,6 +8,7 @@
       "name": "store-client",
       "version": "0.0.0",
       "dependencies": {
+        "@tanstack/react-query": "^5.100.14",
         "react": "^19.1.0",
         "react-dom": "^19.1.0"
       },
@@ -1304,6 +1305,32 @@
         "win32"
       ]
     },
+    "node_modules/@tanstack/query-core": {
+      "version": "5.100.14",
+      "resolved": "https://registry.npmjs.org/@tanstack/query-core/-/query-core-5.100.14.tgz",
+      "integrity": "sha512-5X41dGpxgeaHISCRW2oYwcSycZeULZzAunaudXT9ov1KOTj9xwt0CH6hbwqP1/z74ZWF7rYFnDpyYH07XFcZew==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/tannerlinsley"
+      }
+    },
+    "node_modules/@tanstack/react-query": {
+      "version": "5.100.14",
+      "resolved": "https://registry.npmjs.org/@tanstack/react-query/-/react-query-5.100.14.tgz",
+      "integrity": "sha512-oOr6aRdSFEwWhzxEkD/9ZcItM3+LjBSkeVmadWKwUssAHTsqd/7bOjWrX4AbvEkoEhgAxzN0Xk6H/aYzXiYBAw==",
+      "license": "MIT",
+      "dependencies": {
+        "@tanstack/query-core": "5.100.14"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/tannerlinsley"
+      },
+      "peerDependencies": {
+        "react": "^18 || ^19"
+      }
+    },
     "node_modules/@types/babel__core": {
       "version": "7.20.5",
       "resolved": "https://registry.npmjs.org/@types/babel__core/-/babel__core-7.20.5.tgz",

package.json

@@ -4,12 +4,13 @@
   "version": "0.0.0",
   "type": "module",
   "scripts": {
-    "dev": "vite", 
+    "dev": "vite",
     "build": "vite build",
     "lint": "eslint .",
     "preview": "vite preview"
   },
   "dependencies": {
+    "@tanstack/react-query": "^5.100.14",
     "react": "^19.1.0",
     "react-dom": "^19.1.0"
   },

src/App.jsx

@@ -1,96 +1,93 @@
-import React from 'react'
+import React, {useState, useEffect, useRef } from 'react'
-import styles from './App.module.scss'
+//import { useQuery } from '@tanstack/react-query'
 
-class Clock extends React.Component {
+function useWindowWidth() {
-    constructor(props) {
+    const [width,setWidth] = useState(window.innerWidth)
-        super(props);
-        this.state = { date: new Date() };
-    }
-    componentDidMount() {
-        this.timerId = setInterval( () => this.tick(), 1000);
-    }
-    componentWillUnmount() {
-        clearInterval(this.timerId)
-    }
-    tick() {
-        this.setState({ date: new Date() })
-    }
-    render() {
-        return <div>{this.state.date.toLocaleTimeString()}</div>
-    }
-}
-
-function Clock2() {
-    const [date, setDate] = React.useState(new Date());
     
-    React.useEffect(()=>{
+    useEffect(() => {
-        const timerId = setInterval(()=> setDate(new Date()),1000);
+        const handleResize = () => setWidth(window.innerWidth);
-        return () => clearInterval(timerId);
+        window.addEventListener('resize',handleResize);
+        return () => window.removeEventListener('resize',handleResize);
     },[])
     
-    return <div>{date.toLocaleTimeString()}</div>
+    return width
 }
 
-function MouseTracker() {
+function useLocalStorage(key, initValue) {
-    const [x,setX] = React.useState(0);
+    const [value, setValue] = useState(()=>{
-    const [y,setY] = React.useState(0);
+        const stored = localStorage.getItem(key);
+        return stored !== null ? JSON.parse(stored) : initValue
+    })
     
-    const mouseMoveHandler = event => {
+    useEffect(() => {
-        setX(event.clientX);
+        localStorage.setItem(key, JSON.stringify(value))
-        setY(event.clientY);
+    },[key, value])
-    }
     
-    React.useEffect(()=>{
+    return [value,setValue]
-        document.addEventListener('mousemove', mouseMoveHandler);
+}
-        return () => {
+/*
-            document.removeEventListener('mousemove',mouseMoveHandler);
+function useUserData(userId) {
+    return useQuery(
+        ['user',userId],
+        () => fetch(`/api/user/${userId}`).then(res => res.json()),
+        {refetchOnWindowFocus: false}
+    )
+}*/
+
+function useInput(initValue, validate) {
+    const [value, setValue] = useState(initValue);
+    const [error, setError] = useState(null);
+    
+    const onChange = e => {
+        const newValue = e.target.value
+        setValue(newValue)
+        if (validate) {
+            const validationResult = validate(newValue)
+            setError(validationResult)
         }
-    },[]);
-    
-    return <div className={styles.container}>
-        <p>Координаты мыши:<br /> X:<b>{x}</b>, Y:<b>{y}</b></p>
-        </div>
-}
-
-function DataFetcher() {
-    const [posts,setPosts] = React.useState([]);
-    const [users,setUsers] = React.useState([]);
-    
-    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(() => {
+    return { value, error, onChange }
-        console.log("Компонент создан");
+}
-        getPosts();
+
-        return () => {console.log("Компонент удален");setPosts([])};
+function useInterval(callback, delay) {
-    },[])
+    const savedCallback = useRef()
     
-    return <div><ol>{posts.map(post => <li id={post.id}>{post.title}</li>)}</ol></div>
+    useEffect(()=>{
+        savedCallback.current = callback
+    },[callback]);
+    
+    useEffect(()=>{
+        if (delay == null) return
+        const id = setInterval(()=>{
+            savedCallback.current()
+        },delay);
+        return () => clearInterval(id);
+    },[delay])
 }
 
 function App() {
-    const [tracker,setTracker] = React.useState(false);
+    const width = useWindowWidth();
-    const [dataFetcher,setDataFetcher] = React.useState(false);
+    const [theme, setTheme] = useLocalStorage('theme','light');
+    
+    const username = useInput(
+        '',
+        value => value.length < 3 ? 'минимум 3 символа' : null
+    )
     
 	return (
 		<>
-			<h1>Hello, React!</h1>
+			<h1>Hello, React!{width}</h1>
-            <Clock />
+            <button onClick={()=>{
-            <Clock2 />
+                setTheme(theme === 'light' ? 'dark' : 'light')
-            <button onClick={() => setTracker(!tracker)}>Показать/Скрыть трекер</button>
+            }}>
-            { tracker && <MouseTracker /> }
+                Сменить тему
-            <button onClick={() => setDataFetcher(!dataFetcher)}>Показать/Скрыть посты</button>
+            </button>
-            { dataFetcher && <DataFetcher /> }
+            <p><input type="text" 
+                value={username.value} 
+                onChange={username.onChange} />
+                { username.error ? username.error : '' }
+            </p>
 		</>
 	)
 }

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%;
-    }
-}
-