How to transform .find() results in Mongoose?-CodePudding

I have users collection in my MongoDB with the following schema:

const User = mongoose.Schema({
  gender: {
    type: String
  },
  name: {
    type: String
  },
  location: {
    type: String
  },
  email: {
    type: String
  },
});

Now I need to get the users from the database but in a different schema (or format), the response should like this:

{
  "countries":
    [
      {
        "name": <country>,
         users: [
           {
             "name": <name>,
             "gender": <gender>,
             "email": <email>
           }
        ]
      }
    ]
}

I thought of using User.find() then transform manually the object but It's a long process and i think it might make me query the database multiple times, so I would like to know if there is a way to get the data the way I want with Mongoose directly. If not what do you suggest?

Thanks!

CodePudding user response：

You have to use Mongodb Aggragation Framework . Group by country , then push users to array .

db.collection.aggregate([
  {
    "$group": {
      "_id": "$location",
      "users": {
        "$push": {
          "name": "$name",
          "email": "$email",
          "gender": "$gender"
        }
      }
    }
  },
  {
    "$project": {
      "_id": 0,
      "name": "$_id",
      "users": 1
    }
  },
  {
    "$sort": {
      "name": 1
    }
  }
])

Here is working example : https://mongoplayground.net/p/RI5h5JYOZf8