I have 2 collections with following models:

User:
_id: ObjectID
name: string
org_id: string

Organization:
_id: ObjectID
name: string

I want to create a view that joins them like this:

UserView:
_id: ObjectID
name: string
org_id: string
org_name: string

I created the following lookup in Mongo Compass, which transforms the org_id into an ObjectID in the pipeline $match.

It works, but the resulting org_name is an array instead of a string.

How to make this aggregation to return the required UserView model?

{
  from: "organizations",
  let: {
    objId: {
      $toObjectId: "$org_id"
    }
  },
  pipeline: [
    {
      $match: {
        $expr: {
          $eq: [
            "$_id",
            {
              $toObjectId: "$$objId"
            }
          ]
        }
      }
    },
    {
      $project: {
        _id: 0,
        name: 1
      }
    }
  ],
  as: "org_name"
}