如何最好地查找重复项并合并mongodb集合中的特定字段

db.collection.aggregate([
  {
    $group: {
      _id: { fieldToCheck: "$fieldToCheck" },
      count: { $sum: 1 },
      docs: { $push: "$$ROOT" }
    }
  },
  {
    $match: {
      count: { $gt: 1 }
    }
  },
  {
    $project: {
      _id: 0,
      fieldToCheck: "$_id.fieldToCheck",
      mergedField: {
        $reduce: {
          input: "$docs",
          initialValue: {},
          in: {
            $mergeObjects: ["$$value", "$$this"]
          }
        }
      }
    }
  }
])