// Bad: 3 sequential round trips
const user = await fetchUser();
const posts = await fetchPosts();
const comments = await fetchComments();

// Good: 1 parallel round trip
const [user, posts, comments] = await Promise.all([
  fetchUser(),
  fetchPosts(),
  fetchComments(),
]);

// Bad: always waits even when skipping
async function handle(skip: boolean) {
  let data = await fetchData();
  if (skip) return { skipped: true };
  return process(data);
}

// Good: only waits when needed
async function handle(skip: boolean) {
  if (skip) return { skipped: true };
  let data = await fetchData();
  return process(data);
}

// Bad: profile waits for config unnecessarily
const [user, config] = await Promise.all([fetchUser(), fetchConfig()]);
const profile = await fetchProfile(user.id);

// Good: profile starts as soon as user resolves
const userPromise = fetchUser();
const profilePromise = userPromise.then((user) => fetchProfile(user.id));

const [user, config, profile] = await Promise.all([
  userPromise,
  fetchConfig(),
  profilePromise,
]);

// Bad: sequential execution
export async function loader() {
  let session = await auth();
  let config = await fetchConfig();
  return { session, config };
}

// Good: parallel execution
export async function loader() {
  let sessionPromise = auth();
  let configPromise = fetchConfig();
  const [session, config] = await Promise.all([sessionPromise, configPromise]);
  return { session, config };
}

// Bad: entire page blocked by data
async function Page() {
  let data = await fetchData();
  return (
    <Layout>
      <Content data={data} />
    </Layout>
  );
}

// Good: layout shows immediately, content streams in
function Page() {
  return (
    <Layout>
      <Suspense fallback={<Skeleton />}>
        <Content />
      </Suspense>
    </Layout>
  );
}