Adding document with missing sequence date in mongodb aggregation

Here see this Collection here have a record with createdAt with 14Feb and one with 16Feb, Now querying an aggregation on the collection such as I want to add an document of 15Feb as it was missing in collection with viewCount and clickCount as 0.

So looking for some way to add missing date record/document in aggreagation pipeline.

Pipeline I have

          [
            {
              $group: {
                _id: {
                  $dateToString: { format: "%Y-%m-%d", date: "$createdAt" },
                },
                viewCount: { $sum: "$viewCount" },
                clickCount: { $sum: "$clickCount" },
              },
            },
            { $sort: { _id: 1 } },
            {
              $group: {
                _id: null,
                data: {
                  $push: {
                    k: "$_id",
                    v: { viewCount: "$viewCount", clickCount: "$clickCount" },
                  },
                },
              },
            },
            {
              $project: {
                _id: 0,
                data: { $arrayToObject: "$data" },
              },
            },
          ]```

I looking for some operator in mongo or some way to do this

By combination of both javascript and aggregation pipeline, you can achieve the desired result.

// let's say datesArray has all the dates which are required. 
const datesArray = getDates(formattedFromDate, formattedToDate);


// aggregation pipeLine
    const pipeLine = [
  {
    $group: {
      _id: null,
      data: {
        $push: {
          date: '$date',
          viewCount: '$viewCount',
          clickCount: '$clickCount',
        },
      },
    },
  },
  {
    $project: {
      _id: 0,
      data: {
        $map: {
          input: datesArray,
          in: {
            k: '$$this',
            v: {
              $cond: [
                {
                  $in: ['$$this', '$data.date'],
                },
                {
                  viewCount: {
                    $arrayElemAt: [
                      '$data.viewCount',
                      {
                        $indexOfArray: ['$data.date', '$$this'],
                      },
                    ],
                  },
                  clickCount: {
                    $arrayElemAt: [
                      '$data.clickCount',
                      {
                        $indexOfArray: ['$data.date', '$$this'],
                      },
                    ],
                  },
                },
                {
                  viewCount: 0,
                  clickCount: 0,
                },
              ],
            },
          },
        },
      },
    },
  },
];