aaggregation using lookup and facet

let pref = await Preference.aggregate([
      { $sort: { _id: -1 } },
      {
        $facet: {
          user: [
            {
              $lookup: {
                from: User.collection.name,
                localField: "user",
                foreignField: "_id",
                as: "userData",
              },
            },
            { $unwind: "$userData" },
            {
              $project: {
                // user: 0,
                user: "$userData.displayName",
                // keyword: 0,
              },
            },
          ],
          keyword: [
            {
              $lookup: {
                from: Keyword.collection.name,
                localField: "keyword",
                foreignField: "_id",
                as: "keywordData",
              },
            },
            { $unwind: "$keywordData" },
            {
              $project: {
                // keyword: 0,
                keywordData: {
                  keyword: "$keywordData.keyword",
                  count: "$keywordData.count",
                },
                // user: 0,
              },
            },
          ],
        },
      },
    ]);
    res.json(pref);