From 7607146ff18fb593bea3affb127b1a44b9fc3c23 Mon Sep 17 00:00:00 2001
From: Laktionov Anton <tavres@gmail.com>
Date: Thu, 21 May 2026 20:34:06 +0300
Subject: [PATCH] =?UTF-8?q?=D0=A0=D0=B0=D0=B7=D0=BE=D0=B1=D1=80=D0=B0?=
 =?UTF-8?q?=D0=BB=D0=B8=20useRef?=
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---
 src/App.jsx  | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 src/main.jsx |  2 --
 2 files changed, 90 insertions(+), 4 deletions(-)

diff --git a/src/App.jsx b/src/App.jsx
index 6bf3ac6..a8a2f15 100644
--- a/src/App.jsx
+++ b/src/App.jsx
@@ -1,10 +1,98 @@
-// удаляем все, оставляя лишь пустую функцию App ниже
+import { useState, useRef, useEffect } from 'react'
 
+function Example() {
+    const myRef = useRef(null);
+    const counterRef = useRef(0);
+    const [text, setText] = useState('');
+    
+    useEffect(() => {
+        myRef.current?.focus();
+    },[]);
+        
+    const handlerFocus = () => {
+        if(myRef.current) {
+            myRef.current.focus();
+        }
+    };
+    
+    const handlerChange = (event) => {
+        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() {
+    const countRef = useRef(0);
+    
+    function handlerClick() {
+        countRef.current += 1;
+        //alert(`Нажали ${countRef.current} раз.`);
+    }
+    return <button onClick={handlerClick}>Нажать</button>;
+}
+
+function TimerComponent() {
+    const timerIdRef = useRef(null);
+    
+    useEffect(() => {
+        timerIdRef.current = setTimeout(() => {
+            alert("Прошло 3 секунды");
+        }, 3000);
+        return () => {
+            clearTimeout(timerIdRef.current);
+        }
+    },[]);
+}
+
+function PrevValue({ value }) {
+    const prevValueRef = useRef();
+    
+    useEffect(() => {
+        prevValueRef.current = value;
+    });
+    return (
+        <div>
+            Текущее значение: {value} <br />
+            Предыдущее значение: {prevValueRef.current}
+        </div>
+    )
+}
+
+function ScrollList() {
+    const listRef = useRef(null);
+    
+    const scrollToBottom = () => {
+        if(listRef.current) {
+            listRef.current.scrollTop = listRef.current.scrollHeight;
+        }
+    }
+        
+    return (
+        <>
+            <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 App() {
+    
+    
 	return (
 		<>
-			{/* Добавьте тестовый контент для проверки */}
 			<h1>Hello, React!</h1>
+            <ScrollList />
 		</>
 	)
 }
diff --git a/src/main.jsx b/src/main.jsx
index 950e96a..7e925e8 100644
--- a/src/main.jsx
+++ b/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>
 )