Сделали useReducer для счетчика

src/App.jsx

@@ -1,82 +1,50 @@
-import memo, { useMemo, useCallback, useState } from 'react'
+import { useState, useReducer } from 'react'
 
-function MyComponent() {
+function counterReducer(state, action) {
-    const [count, setCount] = useState(0);
+    switch (action.type) {
-    const [name, setName] = useState('John');
+        case 'increment':
-    
+            return state + 1
-    const greeting = useMemo(() => `Hello, ${name}!`,[name]);
+        case 'decrement':
-    
+            return state - 1
-    return (
+        case 'reset':
-        <>
+            return 0
-        <h2>{greeting}</h2>
+        case 'set_value':
-        <button onClick={()=>setName('Alex')}>New name</button>
+            return action.value
-        </>
+        default:
-    )
+            return state
+    }
 }
 
-function MyComponent2() {
+function Counter() {
-    const [data,setData] = useState([{theme:'light'}])
+    const [count, dispatch] = useReducer(counterReducer,0);
-    const userPreferences = useMemo(()=>({theme: 'dark', language: 'en'}),[]);
-    
-    const processData = useMemo(()=>{
-        return data.map(item => ({ ...item,theme: userPreferences.theme }))
-    },[data, userPreferences]);
-    console.log(processData);
-    return (
-        <>
-            <h2 className={data.theme}>2</h2>
-            <button onClick={()=>setData(data)}>set new theme</button>
-        </>
-    )
-}
-
-function MyComponent3() {
-    const sum = useMemo(()=> a+b,[a,b]);//Бессмысленное применение и вредное
-
-    //Применение оправдано
-    const complexResult = useMemo(()=>{
-        return heavyMethOperations(largeDataSet);
-    },[largeDataSet])
-}
-
-function ParentComponent({ items }) {
-    const [filter, setFilter] = useState('');
-    
-    const listProps = useMemo(()=>({
-            items: items.filter(item => item.name.includes(filter)),
-            onItemClick: id => console.log('Clicked',id),
-            theme: 'dark'
-        }),[items,filter]);
     
     return (
-        <>
+        <div>
-        <Memoized {...listProps} />
+            <span>Счетчик: {count}</span>
-        <button onClick={()=>setFilter('Bob')}>Click</button>
+            <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>
-function Memoized(props) {
-    console.log(props);
-    return (
-        <>
-        <h3 className={props.theme}>Memoized</h3>
-        {props.items.map((item) => (
-         <>
-            <li>
-                {item.name}
-            </li>
-         </>))}
-        </>
     )
 }
 
 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>
-            <ParentComponent items={[{name:'Alex'},{name:'Bob'}]} />
+            <Counter />
 		</>
 	)
 }

src/App.module.scss

@@ -0,0 +1,15 @@
+.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;
+}

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>
 )