parcel.js

const order = [
  {
    width: 8,
    height: 9,
    depth: 7,
  },
  {
    width: 18,
    height: 29,
    depth: 37,
  },
  {
    width: 81,
    height: 92,
    depth: 74,
  },
  {
    width: 104,
    height: 240,
    depth: 30,
  },
];

function isParcelSmallerThanMaxDimensions(parcel, maxDimensions) {
  return (
    parcel.width < maxDimensions &&
    parcel.height < maxDimensions &&
    parcel.depth < maxDimensions
  );
}

function returnsParcelSize(parcel) {
  let result;
  switch (true) {
    case isParcelSmallerThanMaxDimensions(parcel, 10): // make these constants in a separate file instead of hard coding eg: 10
      result = { smallParcel: 3 };
      break;
    case isParcelSmallerThanMaxDimensions(parcel, 50):
      result = { mediumParcel: 5 };
      break;
    case isParcelSmallerThanMaxDimensions(parcel, 100):
      result = { largeParcel: 15 };
      break;
    default:
      result = { extraLargeParcel: 30 };
  }
  return result;
}

function calculateTotal(arrayOfParcels) {
  const arrayOfPrices = arrayOfParcels.map(parcel => Object.values(parcel));
  return arrayOfPrices.reduce((sum, value) => sum + value[0], 0);
}

function createResultObject(array, totalPrice) {
  const result = {};
  array.map(obj => {
    const key = Object.keys(obj)[0];
    result[key] = obj[key];
  });
  result.totalPrice = totalPrice;
  return result;
}

function resultOrchestrator(ordersArray) {
  const parcelSizes = ordersArray.map(parcel => returnsParcelSize(parcel));
  const totalPrice = calculateTotal(parcelSizes);
  return createResultObject(parcelSizes, totalPrice);
}

// To make it work, call the resultOrchestrator function and pass in the order array
// eg: resultOrchestrator(order)