React Server Components erklärt

Willkommen

Die zwei Komponentenwelten

Server Components als Standard

// Server Component (default, no directive needed)
export default async function Page() {
  const data = await fetch('/api/posts').then(r => r.json());
  return <ul>{data.map(p => <li key={p.id}>{p.title}</li>)}</ul>;
}

Client Components

'use client';
import { useState } from 'react';

export function Counter() {
  const [n, setN] = useState(0);
  return <button onClick={() => setN(n+1)}>{n}</button>;
}

Funktionen von Server Components

// Fetch from DB directly in the component!
import { db } from '@/lib/db';

export default async function UserList() {
  const users = await db.select().from(usersTable);
  return <ul>{users.map(u => <li key={u.id}>{u.name}</li>)}</ul>;
}

Einschränkungen von Server Components

Server und Client Components kombinieren

// Server Component
export default async function Page() {
  const user = await getUser();
  return <ProfileEditor user={user} />; // client component
}

// Client Component (separate file)
'use client';
export function ProfileEditor({ user }) {
  const [name, setName] = useState(user.name);
  return <input value={name} onChange={e => setName(e.target.value)} />;
}

Die Client-Boundary-Regel

Kein JavaScript für Server Components

Server Components vs. SSR

Kurztest

Zusammenfassung

Als Nächstes