order-afteropt.js

let promises = []
promises.push(
  Orders
    .find()
    .sort('-create')
    .lean()
    .then((result) => {
      return result;
    })
);

Promise
  .all(promises)
  .then((data) => {
    let objresult = {}
    data.forEach(item => {
      // store data to object[orderid]
      objresult[item.orderid] = item.ordervalue
    })

    // loop object for get data that we want
    Object.keys(objresult).forEach(item => {
      // calculate data
    })

    res.status(200).json({
      reponse
    })

  });