Сделали несколько кастомных хуков

package.json

@@ -10,7 +10,7 @@
     "preview": "vite preview"
   },
   "dependencies": {
-    "info": "^1.0.0",
+    "@tanstack/react-query": "^5.100.14",
     "react": "^19.1.0",
     "react-dom": "^19.1.0"
   },
@@ -23,8 +23,6 @@
     "eslint-plugin-react-hooks": "^5.2.0",
     "eslint-plugin-react-refresh": "^0.4.19",
     "globals": "^16.0.0",
-    "sass": "^1.99.0",
-    "sass-embedded": "^1.99.0",
     "vite": "^6.3.5"
   }
 }

src/App.jsx

@@ -1,29 +1,93 @@
-import styles from './styles/App.module.scss'
-import React, { useState, useCallback } from 'react'
+import React, {useState, useEffect, useRef } from 'react'
+//import { useQuery } from '@tanstack/react-query'
 
-function CounterButton({label, onClick}) {
-    return (
-        <button onClick={onClick} className={styles.counter_button}>{label}</button>
-    )
+function useWindowWidth() {
+    const [width,setWidth] = useState(window.innerWidth)
+    
+    useEffect(() => {
+        const handleResize = () => setWidth(window.innerWidth);
+        window.addEventListener('resize',handleResize);
+        return () => window.removeEventListener('resize',handleResize);
+    },[])
+    
+    return width
 }
-function CounterDisplay({value}) {
-    return (<div className={styles.counter_display}>
-            Значение счетчика: <b>{value}</b>
-    </div>)
+
+function useLocalStorage(key, initValue) {
+    const [value, setValue] = useState(()=>{
+        const stored = localStorage.getItem(key);
+        return stored !== null ? JSON.parse(stored) : initValue
+    })
+    
+    useEffect(() => {
+        localStorage.setItem(key, JSON.stringify(value))
+    },[key, value])
+    
+    return [value,setValue]
+}
+/*
+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 { value, error, onChange }
+}
+
+function useInterval(callback, delay) {
+    const savedCallback = useRef()
+    
+    useEffect(()=>{
+        savedCallback.current = callback
+    },[callback]);
+    
+    useEffect(()=>{
+        if (delay == null) return
+        const id = setInterval(()=>{
+            savedCallback.current()
+        },delay);
+        return () => clearInterval(id);
+    },[delay])
 }
 
 function App() {
-    const [counter,setCounter] = useState(0);
+    const width = useWindowWidth();
+    const [theme, setTheme] = useLocalStorage('theme','light');
     
-    const increment = () => setCounter(prev => prev + 1);
-    const decrement = () => setCounter(prev => prev - 1);
+    const username = useInput(
+        '',
+        value => value.length < 3 ? 'минимум 3 символа' : null
+    )
     
 	return (
 		<>
-            <h2>Практика по созданию счетчика с колбэками</h2>
-            <CounterButton label="Увеличить" onClick={increment} />
-            <CounterButton label="уменьшить" onClick={decrement} />
-            <CounterDisplay value={counter} />
+			<h1>Hello, React!{width}</h1>
+            <button onClick={()=>{
+                setTheme(theme === 'light' ? 'dark' : 'light')
+            }}>
+                Сменить тему
+            </button>
+            <p><input type="text" 
+                value={username.value} 
+                onChange={username.onChange} />
+                { username.error ? username.error : '' }
+            </p>
 		</>
 	)
 }