remove-duplicates-after-facet-in-mongo-db-aggregation

db.collection.aggregate([
  {
    "$facet": {
      "caseByTitle": [
        {
          "$match": {
            "caseTitle": {
              "$regex": ".*godrej.*",
              "$options": "i"
            }
          }
        }
      ],
      "caseByCourtName": [
        {
          "$match": {
            "caseTitle": {
              "$regex": ".*madhya.*",
              "$options": "i"
            }
          }
        }
      ]
    }
  },
  {
    "$addFields": {
      "tempCases": {
        "$concatArrays": [
          "$caseByTitle",
          "$caseByCourtName"
        ]
      }
    }
  },
  {
    $addFields: {
      cases: {
        $reduce: {
          input: "$tempCases",
          initialValue: [],
          in: {
            $concatArrays: [
              "$$value",
              {
                $cond: [
                  {
                    $in: [
                      "$$this._id",
                      "$$value._id"
                    ]
                  },
                  [],
                  [
                    "$$this"
                  ]
                ]
              }
            ]
          }
        }
      }
    }
  },
  {
    "$project": {
      cases: 1
    }
  }
])