function performTask(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

// this wont work as intended
async function asyncFn1() {
  const someTasks = [1, 2, 3, 4, 5];
  let taskSum = 0;
  await someTasks.forEach(async t => {
    await performTask(t);
    taskSum += t;
  });
  console.log("fn1", taskSum); // fn1 0
}

// This works as intended!
async function asyncFn2() {
  const someTasks = [1, 2, 3, 4, 5];
  let taskSum = 0;
  for (t of someTasks) {
    await performTask(t);
    taskSum += t;
  }
  console.log("fn2", taskSum); // fn2 15
}

asyncFn1();
asyncFn2();