Сделали отложеную загрузку и перехват исключений

package-lock.json

@@ -9,7 +9,9 @@
       "version": "0.0.0",
       "dependencies": {
         "react": "^19.1.0",
-        "react-dom": "^19.1.0"
+        "react-dom": "^19.1.0",
+        "react-error-boundary": "^6.1.2",
+        "react-router-dom": "^7.17.0"
       },
       "devDependencies": {
         "@eslint/js": "^9.25.0",
@@ -1600,6 +1602,19 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/cookie": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/cookie/-/cookie-1.1.1.tgz",
+      "integrity": "sha512-ei8Aos7ja0weRpFzJnEA9UHJ/7XQmqglbRwnf2ATjcB9Wq874VKH9kfjjirM6UhU2/E5fFYadylyhFldcqSidQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=18"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/express"
+      }
+    },
     "node_modules/cross-spawn": {
       "version": "7.0.6",
       "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.6.tgz",
@@ -2461,6 +2476,15 @@
         "react": "^19.1.0"
       }
     },
+    "node_modules/react-error-boundary": {
+      "version": "6.1.2",
+      "resolved": "https://registry.npmjs.org/react-error-boundary/-/react-error-boundary-6.1.2.tgz",
+      "integrity": "sha512-3DpCr5HVdZ0caUjYE/kIHBEJN0mNP3ZCgf16c48uJ5TbWjorKVp+YG8W3XqlJ7vJAVNw6wNIImyPXmFydwmyng==",
+      "license": "MIT",
+      "peerDependencies": {
+        "react": "^18.0.0 || ^19.0.0"
+      }
+    },
     "node_modules/react-refresh": {
       "version": "0.17.0",
       "resolved": "https://registry.npmjs.org/react-refresh/-/react-refresh-0.17.0.tgz",
@@ -2471,6 +2495,44 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/react-router": {
+      "version": "7.17.0",
+      "resolved": "https://registry.npmjs.org/react-router/-/react-router-7.17.0.tgz",
+      "integrity": "sha512-FDELK7rTMlCHO5+reyXsPlmfr7N1F91lPHsWYfMEGQm/KQ+F4JFM8jGoeQDmDvdTs93Fw9aSilH+uKRb4/jXvQ==",
+      "license": "MIT",
+      "dependencies": {
+        "cookie": "^1.0.1",
+        "set-cookie-parser": "^2.6.0"
+      },
+      "engines": {
+        "node": ">=20.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=18",
+        "react-dom": ">=18"
+      },
+      "peerDependenciesMeta": {
+        "react-dom": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/react-router-dom": {
+      "version": "7.17.0",
+      "resolved": "https://registry.npmjs.org/react-router-dom/-/react-router-dom-7.17.0.tgz",
+      "integrity": "sha512-fyU2yjGups/hE6Xz0I5ZYbVL8Gx29eCjgpHaRaTaVU+OOAdfRX05KsvyRm0GO8YQwOkhpU3MurW1jyMUJn+zSw==",
+      "license": "MIT",
+      "dependencies": {
+        "react-router": "7.17.0"
+      },
+      "engines": {
+        "node": ">=20.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=18",
+        "react-dom": ">=18"
+      }
+    },
     "node_modules/resolve-from": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/resolve-from/-/resolve-from-4.0.0.tgz",
@@ -2544,6 +2606,12 @@
         "semver": "bin/semver.js"
       }
     },
+    "node_modules/set-cookie-parser": {
+      "version": "2.7.2",
+      "resolved": "https://registry.npmjs.org/set-cookie-parser/-/set-cookie-parser-2.7.2.tgz",
+      "integrity": "sha512-oeM1lpU/UvhTxw+g3cIfxXHyJRc/uidd3yK1P242gzHds0udQBYzs3y8j4gCCW+ZJ7ad0yctld8RYO+bdurlvw==",
+      "license": "MIT"
+    },
     "node_modules/shebang-command": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/shebang-command/-/shebang-command-2.0.0.tgz",

package.json

@@ -4,14 +4,16 @@
   "version": "0.0.0",
   "type": "module",
   "scripts": {
-    "dev": "vite", 
+    "dev": "vite",
     "build": "vite build",
     "lint": "eslint .",
     "preview": "vite preview"
   },
   "dependencies": {
     "react": "^19.1.0",
-    "react-dom": "^19.1.0"
+    "react-dom": "^19.1.0",
+    "react-error-boundary": "^6.1.2",
+    "react-router-dom": "^7.17.0"
   },
   "devDependencies": {
     "@eslint/js": "^9.25.0",

src/App.jsx

@@ -1,60 +1,26 @@
-import { memo, useState, useMemo } from 'react'
+import { Suspense, lazy } from 'react'
+import { ErrorBoundary } from 'react-error-boundary'
 
-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;
-    }
-}
+const LazyComponent = lazy(() => import('./MyComponent'))
 
-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>,[]);
-    
+function ErrorFallBack({error, resetErrorBoundary }) {
     return (
-        <>
-            <Child>
-                {stableChild}
-            </Child>
-            <input type="text" onChange={(e) => setText(e.target.value)} value={text} />
-            <button onClick={() => setCount(count + 1)}>Increment {count}</button>
-        </>
+        <div>
+            <h2>Что то сломалось</h2>
+            <button onClick={resetErrorBoundary}></button>
+        </div>
     )
 }
 
 function App() {
 	return (
 		<>
-			<h1>Hello, React!</h1>
-            <Parent />
-        </>
+			<ErrorBoundary FallBackComponent={ErrorFallBack}>
+                <Suspense fallback={<div>Загрузка ...</div>}>
+			        <LazyComponent />
+                </Suspense>
+            </ErrorBoundary>
+		</>
 	)
 }
 

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>
 )