Next.js: Основы App Router — пример кода

// app/layout.tsx — the ONE layout that must exist. Renders /.
export default function RootLayout({ children }: { children: React.ReactNode }) {
  return (
    
      {children}
    
  );
}

// app/blog/[slug]/page.tsx — a Server Component that fetches directly. No useEffect.
export default async function Post({ params }: { params: Promise }) {
  const { slug } = await params;             // Next 15: params is a Promise
  const post = await getPost(slug);          // runs on the server, secrets safe
  return {post.title};
}

// A leaf that needs interactivity opts INTO the client. Push it to the leaf.
'use client';
import { useState } from 'react';
export function LikeButton() {
  const [liked, setLiked] = useState(false);
  return  setLiked((v) => !v)}>{liked ? '♥' : '♡'};
}