code: function findExistingAdjustment(next) {
        // prepare criteria by _id or fields
        let criteria = _.merge({}, _adjustment);
        criteria = (
          criteria._id ?
          _.pick(criteria, '_id') :
          _.pick(criteria, 'type', 'reason', 'item', 'stock', 'store')
        );
        Adjustment.findOne(criteria, next);
      }
docs: TODO load adjustment by name