CODEWITHSUNDEEP
javascriptnode.jstypescriptpromise
user13000875
user13000875

Reputation: 495

Nodejs resolve promise if execution not completed withing given time

 return await new Promise(function (resolve, reject) {

 //some work goes here

resolve(true)

  });

With Settimeout

 return await new Promise(function (resolve, reject) {

 //some work goes here

setTimeout(function() { resolve(true); }, 5000);

  });

With setTimeout it is waiting for 5 sec even though my task completed in 1 sec. my requirement is if task complete within 5 sec then promise should resolve immediately else it will resolve at 5 sec

Upvotes: 1

Views: 683

Answers (4)

Viraj Singh
Viraj Singh

Reputation: 2349

Here's an example using Promise.race. The idea is in Promise.race we'll do our work and race the work promise against another promise that resolves in a given time (let's say 10s for the below example),

// let's say I've to make a db connection within 10 seconds, else throw an error
const pool = await Promise.race(
    [
        poolPromise, // a db connection promise
        new Promise((_, reject) => setTimeout(
            () => {
                reject("can't establish connection within 10s")
            }, 10e3)
        )
    ]);

Upvotes: 0

Amulya Kashyap
Amulya Kashyap

Reputation: 2373

You can do it like this:

return await new Promise(function (resolve, reject) {
 setTimeout(function() { resolve(true); }, 5000);
 let result = await someworkDone();
 if (result) resolve(result);
});

Here points to note:

  • Specify 5s time before anyone work (statement positing is very important)
  • then get the other work done
  • If your work completes before 5s sec resolve immediately, as above in example.

Upvotes: 0

Jeremy Thille
Jeremy Thille

Reputation: 26380

Clear the timeout when your task completes normally :

return new Promise(function (resolve, reject) {

    let safetyTimeout = setTimeout(resolve, 5000);

    //some work goes here

    // When it's done :

    clearTimeout(safetyTimeout);
    resolve();
});

Upvotes: 2

niour
niour

Reputation: 421

Jeremy Thille answer is the best practice i think with the clearTimout.

Just cause i spended some time to write a piece a code for anyone to use, i post it, maybe it will help someone with their code experiments.

async function test() {
  return new Promise(function (resolve, reject) {
    setTimeout(function () {
      resolve("5 Seconds Passed");
    }, 5000);

    // Some work equivalent to
    someWork(3000, resolve);
  });
}

console.log(await test());

function someWork(time, resolve) {
  // Some work goes here.
  setTimeout(function () {
    console.log("WORK STILL RUNNING");
    resolve("INSIDE 2nd TIMEOUT");
  }, time);
}

Just don't forget to implement Jeremy Thille clearTimeout.

Upvotes: 0

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