Promise All Misuse (ARCH3032)

Key typescript.async.promise-all-misuse · Severity info · Category async

Awaiting independent promises sequentially where Promise.all could parallelize, or using Promise.all where Promise.allSettled is needed to avoid losing results on the first rejection, hurts throughput and correctness.

Incorrect

async function load(): Promise<[User, Order[]]> {
  const user = await fetchUser();    // sequential
  const orders = await fetchOrders(); // independent but waited
  return [user, orders];
}

Correct

async function load(): Promise<[User, Order[]]> {
  const [user, orders] = await Promise.all([fetchUser(), fetchOrders()]);
  return [user, orders];
}

Fix

Parallelize independent operations with Promise.all; use Promise.allSettled when you need to collect partial failures.