动态路由和 generateStaticParams 是如何工作的?

// Tell Next.js the list of slugs to build statically
export async function generateStaticParams() {
  const posts = await getAllPosts();
  return posts.map(post => ({ slug: post.slug }));
  // → builds /blog/post-1, /blog/post-2, ... as static HTML at build time
}

// what happens for a slug NOT returned by generateStaticParams?
export const dynamicParams = true;  // (default) render unknown slugs on-demand (ISR-like)
// export const dynamicParams = false; // return 404 for any slug not pre-built

app/shop/[...categories]/page.tsx  → /shop/a/b/c  (params.categories = ['a','b','c'])
app/[lang]/[slug]/page.tsx         → multiple params: { lang, slug }

export async function generateStaticParams() {
  return [{ lang: "en", slug: "about" }, { lang: "vi", slug: "about" }];
}