Async function doesn't wait with await before returning

Question

Consider the following code:

const getName = () => 
  new Promise(resolve => setTimeout(resolve, 1000, 'xxx'));

f = async () => {
  let name = await getName();
  console.log(name);
  return name;
}

console.log(f());

The function will wait before printing "name" but it will still return the promise instead of the result and won't print the correct output outside the function. Is there a way around this?

Does this answer your question? [How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) — Randy Casburn, Jan 06 '21 at 19:06
@Nonik It is, an arrow function without curly brackets implicitly returns the expression. — Ivar, Jan 06 '21 at 19:09
*"but it will still return the promise instead of the result"* - Async functions always return a Promise, they never directly return the "result". It's up to the consumer (where the function is invoked) to await that promise. — David, Jan 06 '21 at 19:12
If your goal is to wait for `f()` to finish outside of an `async` function, then I'm afraid that is not possible. — Ivar, Jan 06 '21 at 19:12

score 3 · Accepted Answer · answered Jan 06 '21 at 19:09

You need to await for f(). Here is an example:

const getName = () => 
  new Promise(resolve => setTimeout(resolve, 1000, 'xxx'));

const f = async () => {
  const name = await getName();
  console.log("1. "+name);
  return name;
}

const run = (async () => {
  const ret = await f();
  console.log("2. "+ret);
})();

score 2 · Answer 2 · answered Jan 06 '21 at 19:06

2

You need to await the promise returned by the f function. That is why its printing a promise instead of a result.

console.log(await f());

answered Jan 06 '21 at 19:06

Deadron

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That doesn't compile – General Gravicius Jan 06 '21 at 19:08
1

@GeneralGravicius: If this is at the top level (outside an `async` function) then you'd do something like: `f().then(x => console.log(x));` The `await` keyword doesn't work outside of an async function, so you'd use callback syntax instead. (Or wrap it in an async IIFE.) – David Jan 06 '21 at 19:10
1

@David thanks I ended up using an async IIFE – General Gravicius Jan 06 '21 at 19:12

Async function doesn't wait with await before returning

2 Answers2