mongo aggregation

mongo.ts

export function fetchRequestedKernelsList(page: number, rfxType, requestStatus) {
  const match = {
    $or: [
      {
        rfxType: rfxType,
      },
      {
        rfxType: 'both',
      },
    ],
    inactive: {$ne: true},
    requestStatus: requestStatus,
  };
  if (rfxType !== 'rfp' && rfxType !== 'rfi' && rfxType !== 'both') {
    delete match.$or;
  }
  if (requestStatus !== 'requested' && requestStatus !== 'in_progress' &&  requestStatus !== 'completed' ) {
    match.requestStatus = { $exists: true };
  }
  return Promise.await(KernelCollection.collection['aggregate']([
    {
      $match: match,
    },
    {
      $lookup: {
        as: 'enterprise',
        foreignField: '_id',
        from: 'enterprises',
        localField: 'eId',
      },
    },
    {
      $unwind: {
        path: '$enterprise',
        preserveNullAndEmptyArrays: true,
      },
    },
    {
      $project: {
        _id: 1,
        createdAt: 1,
        enterprise: {
          _id: 1,
          name: 1,
        },
        name: 1,
        requestStatus: 1,
        rfxType: 1,
      },
    },
    {
      $skip: ( page - 1) * 20,
    },
    {
      $limit: 20,
    },
    {
      $sort: {
        createdAt: -1,
      },
    },
  ]).toArray());
}