I am struggling with avatar URL update in nested objects array persisted in MongoDB.

Avatar URL needs to be updated from https://old.com/image.jpg to https://new.com/image.jpg

Document structure is at the end of this post. I need to update avatar in three places:

1. organizer.avatar – it works (see below or visit Mongo playground-organizer avatar)
2. meetings[].owner.avatar – similar issue found on StackOverflow, but it does not work beause of different docuement structure (see below or visti Mongo playground-owner avatar)
3. meetings[].participants[].avatar – I have not idea how to handle this.

Update organizer.avatar

It is pretty straightforward as you can see in Mongo playground-organizer avatar.

db.collection.update({},
[
  {
    "$set": {
      "organizer.avatar": {
        $replaceOne: {
          input: "$organizer.avatar",
          find: "https://old.com/",
          replacement: "https://new.com/"
        }
      }
    }
  }
])

Update meetings[].owner.avatar

It iss similar to another issue reported on StackOverflow , but here avatar is nested inside owner object. In this case, operator $mergeObjects does not work as I would expect, because it does not merge objects, but overrides it – see Mongo playground-owner avatar. How to fix this?

db.collection.update({},
[
  {
    "$set": {
      "meetings": {
        $map: {
          input: "$meetings",
          in: {
            $mergeObjects: [
              {
                owner: "$$this.owner"
              },
              {
                owner: {
                  avatar: {
                    $replaceOne: {
                      input: "$$this.owner.avatar",
                      find: "https://old.com/",
                      replacement: "https://new.com/"
                    }
                  }
                }
              }
            ]
          }
        }
      }
    }
  }
])

Update meetings[].participants[].avatar

When it comes to updating meetings[].participants[].avatar – do you have any idea how to handle this?

Example document:

[
  {
    "_id": ObjectId("5a934e000102030405000000"),
    "eventName": "Welcome Event",
    "meetings": [
      {
        "owner": {
          "avatar": "https://old.com/dwight-schrute.png",
          "name": "Dwight Schrute"
        },
        "participants": [
          {
            "avatar": "https://old.com/kevin-malonoe.png",
            "name": "Kevin Malonoe"
          },
          {
            "avatar": "https://old.com/creed-bratton.png",
            "name": "Creed Bratton"
          }
        ]
      },
      {
        "owner": {
          "avatar": "https://old.com/jim-halpert.png",
          "name": "Jim Halpert"
        },
        "participants": [
          {
            "avatar": "https://old.com/pam-beesly.png",
            "name": "Pam Beesly"
          }
        ]
      }
    ],
    "organizer": {
      "avatar": "https://old.com/michale-scott.png",
      "name": "Michael Scott"
    }
  }
]