Promise test

promises.js

function fnThatReturnsPromiseOrValue() {
  const random = Math.random();
  if (random > 0.5) {
    return Promise.resolve(random);
  } else {
    return random;
  }
}

async function naive() {
  let total = 0;
  for (let i = 0; i < 1000_000; i++) {
    total += await fnThatReturnsPromiseOrValue();
  }

  console.log(total);
}

async function testFirst() {
  let total = 0;
  for (let i = 0; i < 1000_000; i++) {
    let result = fnThatReturnsPromiseOrValue();
    if (result instanceof Promise) {
      result = await result;
    }
    total += result;
  }

  console.log(total);
}

console.time("naive");
await naive();
console.timeEnd("naive");

console.time("testFirst");
await testFirst();
console.timeEnd("testFirst");

Hi @jainmohit2001!

Sure, running all promises in parallel would indeed be faster and is the better idea for this particular example.

What I was trying to point out the difference between just awaiting and checking first to see if it's a promise and only awaiting if it is. Doing it a million times was only to multiply the effect to have meaningful numbers :)