เส้นทางซ้อนกันและเลย์เอาต์ Outlet

import { createBrowserRouter, RouterProvider } from 'react-router-dom';

const router = createBrowserRouter([
  {
    path: '/',
    element: <RootLayout />,
    children: [
      { path: 'dashboard', element: <Dashboard /> },
      { path: 'settings', element: <Settings /> },
    ],
  },
]);

function RootLayout() {
  return (
    <div>
      <nav>
        <Link to="/dashboard">Dashboard</Link>
        <Link to="/settings">Settings</Link>
      </nav>
      <main>
        <Outlet /> {/* child route renders here */}
      </main>
    </div>
  );
}

{
  path: '/',
  element: <RootLayout />,
  children: [
    { index: true, element: <Home /> }, // renders at '/'
    { path: 'about', element: <About /> },
  ],
}

const router = createBrowserRouter([
  {
    path: '/app',
    element: <AppShell />,
    children: [
      {
        path: 'users',
        element: <UsersLayout />,
        children: [
          { index: true, element: <UserList /> },
          { path: ':id', element: <UserDetail /> },
        ],
      },
    ],
  },
]);

// Parent layout
function UsersLayout() {
  const [selected, setSelected] = useState(null);
  return <Outlet context={{ selected, setSelected }} />;
}

// Child route
function UserDetail() {
  const { selected } = useOutletContext();
  return <div>{selected}</div>;
}

{
  element: <AuthenticatedLayout />, // no path
  children: [
    { path: '/profile', element: <Profile /> },
    { path: '/billing', element: <Billing /> },
  ],
}

// Inside /app/users — link goes to /app/users/new
function UserList() {
  return <Link to="new">Add User</Link>;
}

function NavLink({ to, children }) {
  const match = useMatch(to);
  return (
    <Link to={to} className={match ? 'active' : ''}>
      {children}
    </Link>
  );
}

{
  path: 'users',
  element: <UsersLayout />,
  errorElement: <UsersError />,
  children: [
    { path: ':id', element: <UserDetail /> },
  ],
}

function DashboardShell() {
  return (
    <div className="dashboard">
      <Sidebar />
      <div className="content">
        <Outlet />
      </div>
    </div>
  );
}