mongodb - exclude a specific field from results array

Question

Below is partnership collection which has users 1 and 2 who participated. One of the users is the current logged in user available as req.user._id and I am listing the user's partners.

{
    "_id": {
        "$oid": "6381697ddddbdb42b4682fb7"
    },
    "users": [{
        "$oid": "user_one_id"
    }, {
        "$oid": "user_two_id"
    }],
}

I am getting the fields of the user who is partner from PartnerModel (excluding the req.user._id). Assuming in this case, req.user._id is user_one_id

let partners =
  await userPartnerModel.find({
    users: { $in: [req.user._id] }
  }).sort({ createdAt: -1 })
    .populate({ 
      path: 'users', 
      select: 'profilePic firstName', 
      model: userModel 
    })

res.status(200).json(partners)

The issue is that partners result also includes the req.user.

The result I am getting now is:

  {
      "users":[
         {
            "firstName":"User One",
            "profilePic":"https://image.jpg",
            "_id":"63729a9a73f736476cbdd0cc"
         },
         {
            "firstName":"User Two",
            "profilePic":"https://image2.jpg",
            "_id":"63728ae473f736476cbdd0be"
         }

But the results should not include req.user._id which is "User One"

Answer 1

Hey you can use the select function to allow only the field you want. By default the _id field is allowed you can disallow it by adding -id . For your case you can use this query:

let partners =
  await userPartnerModel.find({
    users: { $in: [req.user._id] }
  }).sort({ createdAt: -1 })
    .populate({ 
      path: 'users', 
      select: 'profilePic firstName -_id', 
      model: userModel 
    })