Разобрали useRef

package-lock.json

@@ -8,10 +8,8 @@
       "name": "store-client",
       "version": "0.0.0",
       "dependencies": {
-        "immer": "^11.1.8",
         "react": "^19.1.0",
-        "react-dom": "^19.1.0",
-        "zustand": "^5.0.14"
+        "react-dom": "^19.1.0"
       },
       "devDependencies": {
         "@eslint/js": "^9.25.0",
@@ -1369,7 +1367,7 @@
       "version": "19.1.6",
       "resolved": "https://registry.npmjs.org/@types/react/-/react-19.1.6.tgz",
       "integrity": "sha512-JeG0rEWak0N6Itr6QUx+X60uQmN+5t3j9r/OVDtWzFXKaj6kD1BwJzOksD0FF6iWxZlbE1kB0q9vtnU2ekqa1Q==",
-      "devOptional": true,
+      "dev": true,
       "license": "MIT",
       "dependencies": {
         "csstype": "^3.0.2"
@@ -1621,7 +1619,7 @@
       "version": "3.1.3",
       "resolved": "https://registry.npmjs.org/csstype/-/csstype-3.1.3.tgz",
       "integrity": "sha512-M1uQkMl8rQK/szD0LNhtqxIPLpimGm8sOBwU7lLnCpSbTyY3yeU1Vc7l4KT5zT4s/yOxHH5O7tIuuLOCnLADRw==",
-      "devOptional": true,
+      "dev": true,
       "license": "MIT"
     },
     "node_modules/debug": {
@@ -2056,16 +2054,6 @@
         "node": ">= 4"
       }
     },
-    "node_modules/immer": {
-      "version": "11.1.8",
-      "resolved": "https://registry.npmjs.org/immer/-/immer-11.1.8.tgz",
-      "integrity": "sha512-/tbkHMW7y10Lx6i1crLjD4/OhNkRG+Fo7byZHtah0547nIeXYcpIXaUh0IAQY6gO5459qpGGYapcEOHtFXkIuA==",
-      "license": "MIT",
-      "funding": {
-        "type": "opencollective",
-        "url": "https://opencollective.com/immer"
-      }
-    },
     "node_modules/import-fresh": {
       "version": "3.3.1",
       "resolved": "https://registry.npmjs.org/import-fresh/-/import-fresh-3.3.1.tgz",
@@ -2806,35 +2794,6 @@
       "funding": {
         "url": "https://github.com/sponsors/sindresorhus"
       }
-    },
-    "node_modules/zustand": {
-      "version": "5.0.14",
-      "resolved": "https://registry.npmjs.org/zustand/-/zustand-5.0.14.tgz",
-      "integrity": "sha512-/8tAspM5LMPr28b3fwLYrtdj77ECpfZviaP75CMTnwO8ISyaE4GDIG/9rDDYq/cH9D2Xw2A2RXglLInmVBQB/g==",
-      "license": "MIT",
-      "engines": {
-        "node": ">=12.20.0"
-      },
-      "peerDependencies": {
-        "@types/react": ">=18.0.0",
-        "immer": ">=9.0.6",
-        "react": ">=18.0.0",
-        "use-sync-external-store": ">=1.2.0"
-      },
-      "peerDependenciesMeta": {
-        "@types/react": {
-          "optional": true
-        },
-        "immer": {
-          "optional": true
-        },
-        "react": {
-          "optional": true
-        },
-        "use-sync-external-store": {
-          "optional": true
-        }
-      }
     }
   }
 }

package.json

@@ -4,16 +4,14 @@
   "version": "0.0.0",
   "type": "module",
   "scripts": {
-    "dev": "vite",
+    "dev": "vite", 
     "build": "vite build",
     "lint": "eslint .",
     "preview": "vite preview"
   },
   "dependencies": {
-    "immer": "^11.1.8",
     "react": "^19.1.0",
-    "react-dom": "^19.1.0",
-    "zustand": "^5.0.14"
+    "react-dom": "^19.1.0"
   },
   "devDependencies": {
     "@eslint/js": "^9.25.0",

src/App.jsx

@@ -1,10 +1,98 @@
-import Quiz from './components/Quiz'
+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 (
 		<>
-			<h1>Практика по созданию списка задач</h1>
-            <Quiz />
+			<h1>Hello, React!</h1>
+            <ScrollList />
 		</>
 	)
 }

src/components/Question.jsx

@@ -1,31 +0,0 @@
-import { useState } from 'react'
-
-const Question = ({question, onSubmit}) => {
-    const [selectedOption,setSelectedOption] = useState('')
-    const handleSubmit = () => {
-        console.log(selectedOption);
-        if (selectedOption) onSubmit(selectedOption);
-    }
-    
-    return (
-        <div>
-            <h2>Вопрос {question.id}: {question.text}</h2>
-            <div>
-                {question.options.map((option, index)=>(
-                    <label key={index}>
-                        <input 
-                        type="radio" 
-                        name={`question-${question.id}`}
-                        value={option}
-                        checked={selectedOption === option}
-                        onChange={() => setSelectedOption(option)} />
-                        {option}
-                    </label>
-                ))}
-            </div>
-            <button onClick={handleSubmit} >Следующий вопрос</button>
-        </div>
-    )
-}
-
-export default Question

src/components/Quiz.jsx

@@ -1,35 +0,0 @@
-import useQuizStore from './store/useQuizStore'
-import Question from './Question'
-import Result from './Result'
-
-const Quiz = () => {
-    const {
-        questions,
-        currentQuestion,
-        userAswers,
-        isFinished,
-        submitAnswer,
-        goToNextQuestion,
-        restartQuiz,
-    } = useQuizStore();
-    
-    const handleAnswerSubmit = (anwser) => {
-        console.log('Yes')
-        submitAnswer(answer)
-        if (currentQuestion < questions.length - 1 ) {
-            goToNextQuestion()
-        }
-    }
-    if(isFinished) {
-        return (<Result />)
-    }
-    return (
-        <div className="quiz">
-            <Question 
-            question={questions[currentQuestion]} 
-            onSubmit={handleAnswerSubmit} />
-        </div>
-    )
-}
-
-export default Quiz

src/components/Result.jsx

@@ -1,9 +0,0 @@
-const Result = ({questions, userAswers, onRestart}) => {
-    return (
-        <div>
-            <h2>Результат</h2>
-            <button onClick={onRestart}>Начать заново</button>
-        </div>
-    )
-}
-export default Result

src/components/store/useQuizStore.jsx

@@ -1,36 +0,0 @@
-import { create } from 'zustand'
-
-const useQuizStore = create(set => ({
-    questions: [
-        {
-            id:1,
-            text: 'Сколько будет 2+2?',
-            options: ['3','4','2'],
-            correctAnswer: '4',
-        },
-        {
-            id:2,
-            text: 'Столица России?',
-            options: ['Москва','Париж','Лондон'],
-            correctAnswer: 'Москва',
-        },
-    ],
-    currentQuestion: 0,
-    userAnswer:[],
-    isFinished: false,
-    goToNextQuestion: () => set(state => ({
-            currentQuestion: state.currentQuestion + 1,
-    })),
-    submitAnswer: answer => set(state => {
-        const updatedAnswer = [...state.userAnswer, answer];
-        const isFinished = (state.currentQuestion >= state.questions.length - 1);
-        return {userAnswer: updatedAnswer, isFinished};
-    }),/*
-    restartQuiz: () => set({
-        currentQuestion: 0,
-        userAnswer: [],
-        isFinished: false
-    }),     */
-}))
-
-export default useQuizStore