async_await_not_workking_with_foreach.md

async/await not working with forEach()

INSTEAD USE for...of forEach() expects a synchronous function and won’t do anything with the return value. It just calls the function and on to the next. for...of will actually await on the result of the execution of the function.

const example = async () => {
  const nums = [1,2,3];
  nums.forEach(async num => {
   const result = await returnNum(num);
   console.log(result);
  });
  console.log('after forEach');
}

const returnNum = x => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(x);
    }, 500);
  });
}

example().then(() =>{
  console.log('done');
});
/*
    The result:
    after forEach
    done
    1
    2
    3
*/

const example = async () => {
  const nums = [1,2,3];
  for (const num of nums) {
   const result = await returnNum(num);
   console.log(result);
  }
  console.log('after forEach');
}

const returnNum = x => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve(x);
    }, 500);
  });
}

example().then(() => {
  console.log('done');
})
/*
    The result:
    1
    2
    3
    after foreach
    done
*/