QRG: await vs Promise.all: Awaiting Arrays of Promises

🧠 Quick Reference: Awaiting Arrays of Promises

❗ Problem

You called an async function that returns an array of promises and expected this to work:

const result = await myAsyncBatchFunction(); // ❌ Doesn't work as expected

But result is still an array of unresolved Promise objects.

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✅ Fix

Use Promise.all(...) to await the entire array:

const result = await Promise.all(myAsyncBatchFunction()); // ✅ Now resolved

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🔍 Why?

• await unwraps one Promise
• An array of promises is not a promise itself
• Promise.all([...]) returns a single promise that resolves to an array of resolved values

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🧪 Example

async function fetchAll() {
  return [fetchUser(), fetchPosts()];
}

const result = await fetchAll(); // ❌ result is [Promise, Promise]
const resolved = await Promise.all(fetchAll()); // ✅ resolved is [user, posts]

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💡 Rule of Thumb

If you're awaiting something that returns multiple things, and they're async, wrap it in Promise.all() — even if it's from an async function.