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

@@ -1,82 +1,93 @@
-import memo, { useMemo, useCallback, useState } from 'react'
+import React, {useState, useEffect, useRef } from 'react'
+//import { useQuery } from '@tanstack/react-query'
 
-function MyComponent() {
-    const [count, setCount] = useState(0);
-    const [name, setName] = useState('John');
+function useWindowWidth() {
+    const [width,setWidth] = useState(window.innerWidth)
     
-    const greeting = useMemo(() => `Hello, ${name}!`,[name]);
+    useEffect(() => {
+        const handleResize = () => setWidth(window.innerWidth);
+        window.addEventListener('resize',handleResize);
+        return () => window.removeEventListener('resize',handleResize);
+    },[])
     
-    return (
-        <>
-        <h2>{greeting}</h2>
-        <button onClick={()=>setName('Alex')}>New name</button>
-        </>
-    )
+    return width
 }
 
-function MyComponent2() {
-    const [data,setData] = useState([{theme:'light'}])
-    const userPreferences = useMemo(()=>({theme: 'dark', language: 'en'}),[]);
+function useLocalStorage(key, initValue) {
+    const [value, setValue] = useState(()=>{
+        const stored = localStorage.getItem(key);
+        return stored !== null ? JSON.parse(stored) : initValue
+    })
     
-    const processData = useMemo(()=>{
-        return data.map(item => ({ ...item,theme: userPreferences.theme }))
-    },[data, userPreferences]);
-    console.log(processData);
-    return (
-        <>
-            <h2 className={data.theme}>2</h2>
-            <button onClick={()=>setData(data)}>set new theme</button>
-        </>
+    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 MyComponent3() {
-    const sum = useMemo(()=> a+b,[a,b]);//Бессмысленное применение и вредное
-
-    //Применение оправдано
-    const complexResult = useMemo(()=>{
-        return heavyMethOperations(largeDataSet);
-    },[largeDataSet])
-}
-
-function ParentComponent({ items }) {
-    const [filter, setFilter] = useState('');
+function useInterval(callback, delay) {
+    const savedCallback = useRef()
     
-    const listProps = useMemo(()=>({
-            items: items.filter(item => item.name.includes(filter)),
-            onItemClick: id => console.log('Clicked',id),
-            theme: 'dark'
-        }),[items,filter]);
+    useEffect(()=>{
+        savedCallback.current = callback
+    },[callback]);
     
-    return (
-        <>
-        <Memoized {...listProps} />
-        <button onClick={()=>setFilter('Bob')}>Click</button>
-        </>
-    )
-}
-
-function Memoized(props) {
-    console.log(props);
-    return (
-        <>
-        <h3 className={props.theme}>Memoized</h3>
-        {props.items.map((item) => (
-         <>
-            <li>
-                {item.name}
-            </li>
-         </>))}
-        </>
-    )
+    useEffect(()=>{
+        if (delay == null) return
+        const id = setInterval(()=>{
+            savedCallback.current()
+        },delay);
+        return () => clearInterval(id);
+    },[delay])
 }
 
 function App() {
+    const width = useWindowWidth();
+    const [theme, setTheme] = useLocalStorage('theme','light');
+    
+    const username = useInput(
+        '',
+        value => value.length < 3 ? 'минимум 3 символа' : null
+    )
+    
 	return (
 		<>
-			{/* Добавьте тестовый контент для проверки */}
-			<h1>Hello, React!</h1>
-            <ParentComponent items={[{name:'Alex'},{name:'Bob'}]} />
+			<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>
 		</>
 	)
 }

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>
 )