MongoDB Aggregate Example

dummy.js

const docs = await Entry.aggregate([
  { $match: { compId: { $eq } } },
  { $group: { _id: '$userId', data: { $push: { userId: '$userId' } }, count: { $sum: 1 } } },
  {
    $lookup: {
      from: 'users', localField: 'data.userId', foreignField: '_id', as: 'userData',
    },
  },
  { $unwind: '$userData' },
  {
    $project: {
      count: 1,
      name: '$userData.name',
      participant: '$userData.participant',
    },
  },
]);