Конец урока

src/App.jsx

@@ -1,60 +1,67 @@
-import { memo, useState, useMemo } from 'react'
+import React, { useState, useReducer, useRef, memo } from 'react'
 
-function memoize(fn) {
-    const cache = new Map();
-    return function(...args) {
-        const key = JSON.stringify(args);
-        if (cache.has(key)) {
-            return cache.get(key);
-        }
-        const result = fn.apply(this, args);
-        cache.set(key,result);
-        return result;
+function tasksReducer(state, action) {
+    switch(action.type) {
+        case 'ADD_TASK':
+            return [...state, action.payload]
+        case 'TOGGLE_TASK':
+            return state.map(task => task.id === action.payload ? {...task, complite: !task.complite} : task)
+        case 'REMOVE_TASK':
+            return state.filter(task => task.id !== action.payload)
+        default:
+            return state
     }
 }
 
-function fibonachi(n, memo={}) {
-    if (n in memo) {console.log(n);return memo[n];}
-    if (n <= 1) return 1;
-    memo[n] = fibonachi(n-1, memo) + fibonachi(n - 2, memo);
-    return memo[n];
-}
-
-const MyComponent = ({ value }) => {
-    console.log('Rendring');
-    return <div>{value}</div>
-}
-
-const MemoizedComponent = memo(MyComponent);
-
-const Child = memo(({ children }) => {
-    console.log('Child component rendred');
-    return <div>{children}</div>;
-});
-
-const Parent = () => {
-    const [count,setCount] = useState(0);
-    const [text, setText] = useState('');
-    
-    const stableChild = useMemo(() => <span>Memo text</span>,[]);
-    
+const TaskList = memo(function TaskList({tasks, onToggle, onRemove}) {
+    console.log("Rendred")
     return (
-        <>
-            <Child>
-                {stableChild}
-            </Child>
-            <input type="text" onChange={(e) => setText(e.target.value)} value={text} />
-            <button onClick={() => setCount(count + 1)}>Increment {count}</button>
-        </>
+        <ul>
+        {tasks.map(({id, text, complite}) => (
+                <li key={id}
+                    style={{textDecoration: complite ? 'line-through' : 'none' }}>
+                    <input type="checkbox" checked={complite} onChange={()=>onToggle(id)} />
+                    {text}
+                    <button onClick={()=> onRemove(id)} style={{marginLeft: 10}}>
+                        Удалить
+                    </button>
+                </li>
+            ))}
+        </ul>
     )
-}
+})
 
 function App() {
+    const [tasks, dispatch] = useReducer(tasksReducer,[])
+    const [input,setInput] = useState('')
+    const [error,setError] = useState('')
+    const inputRef = useRef(null)
+    
+    const addTask = () => {
+        if (input.trim() === '') {
+            setError('Пустой текст задачи')
+            return
+        }
+        setError('')
+        dispatch({
+            type: 'ADD_TASK',
+            payload: {id: Date.now(), text: input.trim(), complite: false }
+        })
+        setInput('')
+        inputRef.current.focus()
+    }
+    
 	return (
-		<>
-			<h1>Hello, React!</h1>
-            <Parent />
-        </>
+		<div style={{padding: 20}}>
+			<h1>Список дел</h1>
+			<input ref={inputRef} value={input} onChange={e => setInput(e.target.value)} />
+			<button onClick={addTask}>Добавить</button>
+            {error && <p style={{color: 'red'}}>{error}</p>}
+            
+            <TaskList tasks={tasks} 
+                onToggle={id => dispatch({type: 'TOGGLE_TASK', payload: id})}
+                onRemove={id => dispatch({type: 'REMOVE_TASK', payload: id})} />
+		</div>
 	)
 }
 

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>
 )