Create array of elements based on another existing array using MongoDB Aggregation

I need to take a field from a document as input, like below:

"participants": ["John", "Peter"],

and make the output field like that:

"participants": [
    {
        "name": null,
        "identifier": "John",
        "type": "individual",
    },
    {
        "name": null,
        "identifier": "Peter",
        "type": "individual",
    },
]

Basically, the idea is get every element of an array and "replace it" by a structure/map with multiple fields.

I tried to do it by unwinding the participants field and regrouping everything pushing the field inside the new structure, but certainly there's a better way to do it... Right?

Use $map to iterate through the array and augment the entries, in an update with aggregation pipeline.

db.collection.update({},
[
  {
    "$set": {
      "participants": {
        "$map": {
          "input": "$participants",
          "as": "p",
          "in": {
            "name": null,
            "identifier": "$$p",
            "type": "individual"
          }
        }
      }
    }
  }
])

Mongo Playground