在我的mongodb数据库中，我有如下数据：

{ id: 'ran1', code: 'ABC1', createdAt: 'Sep 1 2022', count: 5 } 
{ id: 'ran2', code: 'ABC1', createdAt: 'Sep 2 2022', count: 3 } 
{ id: 'ran3', code: 'ABC2', createdAt: 'Sep 1 2022', count: 2 } 
{ id: 'ran4', code: 'ABC1', createdAt: 'Oct 1 2022', count: 1 } 
{ id: 'ran5', code: 'ABC1', createdAt: 'Oct 2 2022', count: 2 } 
{ id: 'ran6', code: 'ABC2', createdAt: 'Ocr 1 2022', count: 1 }

现在，作为输出，我需要10月份的所有数据，但我还需要计算和比较百分比。

{code: 'ABC1', totalCount: the sum of total count of oct (1+2) =3 , percent: (total count of oct - total count of sep)/total count of oct * 100 } 
{code: 'ABC2', totalCount: 1, percent: -100}

我尝试使用两个不同的聚合来实现这些输出，然后将当前月份的聚合与上个月聚合中的每个元素进行Map。
这是我的代码

const { filterDate, shop } = req.query;
      const splittedFilter = filterDate.split("-");

      const query = {
        shopUrl: { $regex: shop, $options: "i" },
        createdAt: {
          $gte: new Date(splittedFilter[0]),
          $lte: new Date(splittedFilter[1]),
        },
      };

      const currentCodes = await BlockedCode.aggregate([
        {
          $match: query,
        },
        {
          $group: {
            _id: "$discountCode",
            totalCount: { $sum: "$count" },
          },
        },
      ]);
      const prevQuery = {
        shopUrl: { $regex: shop, $options: "i" },
        createdAt: {
          $gte: new Date(splittedFilter[2]),
          $lte: new Date(splittedFilter[3]),
        },
      };
      const previousCodes = await BlockedCode.aggregate([
        {
          $match: prevQuery,
        },
        {
          $group: {
            _id: "$discountCode",
            totalCount: { $sum: "$count" },
          },
        },
      ]);

      const result = currentCodes.map((code) => {
        const foundPrevCode = previousCodes.find((i) => i._id === code._id);

        if (foundPrevCode?._id) {
          const prevCount = foundPrevCode?.totalCount;
          const currCount = code?.totalCount;
          const difference = currCount - prevCount;
          const percentage = (difference / currCount) * 100;
          return { ...code, percentage };
        } else {
          return { ...code, percentage: 100 };
        }
      });