collectionSum

collectionSum.js

const collectionSum = (collection) => {
  const iterator = collection.iterator();
  
  let eachIteration;
  let sum = 0;
  
  while ((eachIteration = iterator(), !eachIteration.done)) {
    sum += eachIteration.value;
  }
  
  return sum;
}

collectionSum(stack)