■P272

app/layout.js
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const RootLayout = ({ children }) => {
  return (
    <html lang="ja">
      <body>
        <header>
          <h1>Next Book App</h1>
        </header>
        {children}
        <footer>copyright Next Book App 2025</footer>
      </body>
    </html>
  );
};

export default RootLayout;
────────────────


■P273

app/foo/layout.js
────────────────
const Layout = ({ children }) => {
  return (
    <>
      <nav>
        <a href="/foo">foo</a>/<a href="/foo/bar">bar</a>
      </nav>
      {children}
    </>
  );
};

export default Layout;
────────────────

