Program terminates after await statement in javascript

Question

I am learning async javascript, and I am struck with a doubt here. Here is my simple code:

function delay(sec)
{
    return new Promise(()=>{
        setTimeout(()=>{
            console.log("Inside settimeout");
        },sec);
    })
}

async function print()
{
    await delay(2000);
    console.log("Outside settimeout");
}

print();

In the above program I expected that due to await keyword, the delay function will wait for 2 seconds, output "Inside settimeout" and then output "Outside settimeout". But instead, it just logs "Inside settimeout" and simply terminates without logging "Outside settimeout". Can someone clear my doubt and explain how this works? Thanks in advance.

You need to call the resolve() function inside your delay function. — Kostas Minaidis, Sep 19 '22 at 08:56
Does this answer your question? [Combination of async function + await + setTimeout](https://stackoverflow.com/questions/33289726/combination-of-async-function-await-settimeout) — Ivar, Sep 19 '22 at 09:00

score 1 · Accepted Answer · answered Sep 19 '22 at 08:58

1

You are missing the resolve call in your promise.

function delay(sec)
{
    return new Promise((resolve, reject)=>{
        setTimeout(()=>{
            console.log("Inside settimeout");
            resolve();
        },sec);
    })
}

async function print()
{
    await delay(2000);
    console.log("Outside settimeout");
}

print();

answered Sep 19 '22 at 08:58

Igor Janković

5,494
6
32
46

I got it...But why did it terminate without logging "Outside settimeout" – tdcoder Sep 19 '22 at 09:09
2

@tdcoder Because the "await" waits for the Promise to resolve, if it doesn't resolve it will wait forever. – Xion 14 Sep 19 '22 at 09:12

score 0 · Answer 2 · answered Sep 19 '22 at 08:58

0

You have a Promise that never resolves since you never call the resolve function. Here would be the fixed function.

function delay(ms = 0) {
  return new Promise((resolve, reject) => setTimeout(resolve ,ms))
}

answered Sep 19 '22 at 08:58

Xion 14

427
2
8

Program terminates after await statement in javascript

2 Answers2