Compare commits

..

3 Commits

Author SHA1 Message Date
laktionov-as 8cc72afd7b final 2026-05-28 19:16:14 +03:00
laktionov-as a520406547 useCallback with React.memo 2026-05-26 21:28:43 +03:00
laktionov-as 38f7195ed4 useCallback 2026-05-26 21:17:42 +03:00
3 changed files with 30 additions and 52 deletions
+30 -35
View File
@@ -1,50 +1,45 @@
import { useState, useReducer } from 'react'
import React, { useMemo, useCallback, useState } from 'react'
function counterReducer(state, action) {
switch (action.type) {
case 'increment':
return state + 1
case 'decrement':
return state - 1
case 'reset':
return 0
case 'set_value':
return action.value
default:
return state
}
}
const TodoItem = React.memo(({ item, onToggle, onDelete }) => {
console.log(`rendred ${item.id}`);
return <li>
{item.name}
<button onClick={() => onToggle(item.id)}>Done</button>
<button onClick={() => onDelete(item.id)}>remove</button>
</li>
})
function Counter() {
const [count, dispatch] = useReducer(counterReducer,0);
function ItemList({ items }) {
const handleToggle = useCallback(id => {
items.done = true;
console.log(`Item ${id} done`)
console.log(id)
},[]);
const handleDelete = useCallback(id => {
items.pop(id);
},[]);
return (
<div>
<span>Счетчик: {count}</span>
<button onClick={()=> dispatch({type: 'increment'})}>+</button>
<button onClick={()=> dispatch({type: 'decrement'})}>-</button>
<button onClick={()=> dispatch({type: 'reset'})}>reset</button>
<button onClick={()=> dispatch({type: 'set_value', value: 5})}>set 5</button>
</div>
<>
<h3>List items</h3>
{items.map(item => (
<TodoItem key={item.id} item={item}
onToggle={handleToggle} onDelete={handleDelete} />
))}
</>
)
}
function App() {
const [tasks, setTasks] = useState([])
const [filter, setFilter] = useState('all')
const [sortBy,setSortBy] = useState('date')
const addTask = newTask => {
setTasks([...tasks,newTask])
}
return (
<>
{/* Добавьте тестовый контент для проверки */}
<h1>Hello, React!</h1>
<Counter />
<ItemList items={[
{id:1,name:'Первый',done:false},
{id:2,name:'Второй',done:false}
]} />
</>
)
}
-15
View File
@@ -1,15 +0,0 @@
.container {
/* display: flex;
flex-direction: column;
flex-wrap: nowrap;*/
height: 500px;
overflow: auto;
border: 1px solid black;
}
.item {
font-size: 16pt;
border: 1px dotted gray;
/*margin: 5px 10px;
padding: 10px;*/
border-radius: 5px;
}
-2
View File
@@ -4,7 +4,5 @@ import { createRoot } from 'react-dom/client'
import App from './App.jsx'
createRoot(document.getElementById('root')).render(
<StrictMode>
<App />
</StrictMode>
)