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for await of VS Promise.all

Amjad Saeed answered on February 15, 2024 Popularity 3/10 Helpfulness 1/10

answer for await of VS Promise.all

for await of VS Promise.all

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As you said Promise.all will send all the requests in one go and then you will get the response when all of them gets completed.

In the second scenario, you will send the request in one go but recieve response as for each one by one.

See this small example for reference.

let i = 1;
function somethingAsync(time) {
  console.log("fired");
  return delay(time).then(() => Promise.resolve(i++));
}
const items = [1000, 2000, 3000, 4000];

function delay(time) {
  return new Promise((resolve) => { 
      setTimeout(resolve, time)
  });
}

(async() => {
  console.time("first way");
  const promises = await Promise.all(items.map(e => somethingAsync(e)));
  for (const res of promises) {
    console.log(res);
  }
  console.timeEnd("first way");

  i=1; //reset counter
  console.time("second way");
  for await (const res of items.map(e => somethingAsync(e))) {
    // do some calculations
    console.log(res);
  }
  console.timeEnd("second way");
})();

Popularity 3/10 Helpfulness 1/10 Language javascript

Source: stackoverflow.com

Tags: for-await javascript promise.all

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Contributed on Feb 15 2024

Amjad Saeed

0 Answers Avg Quality 2/10

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