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Author SHA1 Message Date
laktionov-as de33066cbe Практика 2026-06-11 20:13:10 +03:00
4 changed files with 62 additions and 91 deletions
+11
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@@ -8,6 +8,7 @@
"name": "store-client",
"version": "0.0.0",
"dependencies": {
"immer": "^11.1.8",
"react": "^19.1.0",
"react-dom": "^19.1.0"
},
@@ -2054,6 +2055,16 @@
"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",
+2 -1
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@@ -4,12 +4,13 @@
"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"
},
+41 -90
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@@ -1,98 +1,49 @@
import { useState, useRef, useEffect } from 'react'
import React, { useState, useEffect } from 'react'
import { produce } from 'immer'
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() {
const [tasks,setTasks] = useState([])
const [input,setInput] = useState('')
const addTask = () => {
if(!input.trim()) return
setTasks(currentTasks => produce(currentTasks, draft => {
draft.push({
id: Date.now(),
text: input.trim(),
done: false
})
}))
setInput('')
}
const toggleTask = id => {
setTasks(currentTask => produce(currentTask, draft => {
const task = draft.find(t => t.id === id)
if(task) {
task.done = !task.done
}
}))
}
const removeTask = id => {
setTasks(currentTask => produce(currentTask, draft => {
const index = draft.findIndex(t => t.id === id)
if (index !== -1)
draft.splice(index,1)
}))
}
return (
<>
<h1>Hello, React!</h1>
<ScrollList />
<h1>Практика по созданию списка задач</h1>
<input value={input} onChange={e=>setInput(e.target.value)} />
<button onClick={addTask}>Добавить</button>
<ul>{tasks.map(({id,text,done}) => (
<li key={id} style={{ textDecoration: done ? 'line-through' : 'none'}}>
<input type="checkbox" checked={done} onChange={()=> toggleTask(id)} />
{text}
<button onClick={() => removeTask(id)}>Удалить</button>
</li>
))}</ul>
</>
)
}
+8
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@@ -0,0 +1,8 @@
export function MyComponent() {
return (
<>
<h1>Hello</h1>
</>
)
}
export default MyComponent