NodeJs - Async/Await inside controller [duplicate]

Question

I have this simple example to my controller and doesn't work as expected

export let create = async (req: Request, res: Response) => { console.log("START"); await setTimeout(() => { console.log("MIDDLE"); }, 1000); console.log("END"); return res.json({ data: null }); };

Output: START,END,MIDDLE

EXPECT: START,MIDDLE,END

setTimeout returns a number, not a promise. Only if you await a promise does the execution actually "wait". — Felix Kling
– Felix Kling, Commented Dec 27, 2017 at 14:31

Lev Kuznetsov · Accepted Answer · 2017-12-27 14:32:27Z

2

try:

await new Promise(resolve => setTimeout(resolve, 1000))

answered Dec 27, 2017 at 14:32

Lev Kuznetsov

3,8085 gold badges22 silver badges36 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Peter Carter · Accepted Answer · 2017-12-27 15:07:23Z

You're using setTimeOut without creating the promise object, so it's waiting for the setTimeOut value to be returned (which is instant) rather than waiting for a promise resolution. This is the reason your await statement isn't working the way it was intended to. What you need is to create a promise:

function resolveAfterOneSecond(x) { return new Promise(resolve => { setTimeout(() => { console.log("Middle"); resolve(x); }, 1000); }); } async function f1() { var x = await resolveAfterOneSecond(10); console.log("End"); } console.log("Begin"); f1();

and then set your function to await the return of the promise, rather than the return of the setTimeOut function integer.

Collectives™ on Stack Overflow

NodeJs - Async/Await inside controller [duplicate]

2 Answers 2

Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Linked

Related