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

@@ -1,98 +1,93 @@
-import { useState, useRef, useEffect } from 'react'
+import React, {useState, useEffect, useRef } from 'react'
+//import { useQuery } from '@tanstack/react-query'
 
-function Example() {
+function useWindowWidth() {
-    const myRef = useRef(null);
+    const [width,setWidth] = useState(window.innerWidth)
-    const counterRef = useRef(0);
-    const [text, setText] = useState('');
     
     useEffect(() => {
-        myRef.current?.focus();
+        const handleResize = () => setWidth(window.innerWidth);
-    },[]);
+        window.addEventListener('resize',handleResize);
-        
+        return () => window.removeEventListener('resize',handleResize);
-    const handlerFocus = () => {
+    },[])
-        if(myRef.current) {
-            myRef.current.focus();
-        }
-    };
     
-    const handlerChange = (event) => {
+    return width
-        setText(event.target.value);
-    }
-    counterRef.current += 1;
-    return <div>
-        <input ref={myRef} text="text" /><br />
-        Количество рендров: {counterRef.current}<br />
-        <input text="text" onChange={handlerChange} value={text} />
-        <button onClick={handlerFocus}>Поставить фокус на поле</button>
-    </div>
 }
 
-function ClickCounter() {
+function useLocalStorage(key, initValue) {
-    const countRef = useRef(0);
+    const [value, setValue] = useState(()=>{
-    
+        const stored = localStorage.getItem(key);
-    function handlerClick() {
+        return stored !== null ? JSON.parse(stored) : initValue
-        countRef.current += 1;
+    })
-        //alert(`Нажали ${countRef.current} раз.`);
-    }
-    return <button onClick={handlerClick}>Нажать</button>;
-}
-
-function TimerComponent() {
-    const timerIdRef = useRef(null);
     
     useEffect(() => {
-        timerIdRef.current = setTimeout(() => {
+        localStorage.setItem(key, JSON.stringify(value))
-            alert("Прошло 3 секунды");
+    },[key, value])
-        }, 3000);
-        return () => {
-            clearTimeout(timerIdRef.current);
-        }
-    },[]);
-}
-
-function PrevValue({ value }) {
-    const prevValueRef = useRef();
     
-    useEffect(() => {
+    return [value,setValue]
-        prevValueRef.current = value;
+}
-    });
+/*
-    return (
+function useUserData(userId) {
-        <div>
+    return useQuery(
-            Текущее значение: {value} <br />
+        ['user',userId],
-            Предыдущее значение: {prevValueRef.current}
+        () => fetch(`/api/user/${userId}`).then(res => res.json()),
-        </div>
+        {refetchOnWindowFocus: false}
     )
-}
+}*/
 
-function ScrollList() {
+function useInput(initValue, validate) {
-    const listRef = useRef(null);
+    const [value, setValue] = useState(initValue);
+    const [error, setError] = useState(null);
     
-    const scrollToBottom = () => {
+    const onChange = e => {
-        if(listRef.current) {
+        const newValue = e.target.value
-            listRef.current.scrollTop = listRef.current.scrollHeight;
+        setValue(newValue)
+        if (validate) {
+            const validationResult = validate(newValue)
+            setError(validationResult)
         }
     }
-        
+    
-    return (
+    return { value, error, onChange }
-        <>
-            <div ref={listRef} 
-               style={{height: 200, overflowY: 'auto', border: '1px solid black'}}>
-                {[...Array(20)].map((_,i)=>(
-                    <div key={i}>Элемент № {i + 1}</div>
-                ))}
-            </div>
-            <button onClick={scrollToBottom}>Прокрутить вниз</button>
-        </>
-    )
 }
-        
+
+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 width = useWindowWidth();
+    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>
-            <ScrollList />
+            <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>
 )