Async and Await

An async function always returns a Promise. await suspends that function, not the entire thread or event loop.

Preserve concurrency

async function dashboard() {
  const profileTask = fetchProfile();
  const activityTask = fetchActivity();
  try {
    const [profile, activity] = await Promise.all([profileTask, activityTask]);
    return { profile, activity };
  } catch (error) {
    throw new Error("Dashboard failed", { cause: error });
  }
}

Start independent operations before awaiting together; sequential awaits are correct only for dependencies. Use try/catch around the boundary that can recover or add context. Await async results or intentionally mark fire-and-forget work with error handling. for await...of consumes async iterables with backpressure-like sequential demand.