Nested maps in mongoose schema - mongodb

Question

I'm currently creating a fitting mongoose schema for our new JSON format.
It is not very complex but I ran into the issue that certain values are not saved as array but rather as "normalized array" like this:
answers: [{value: 5, string: "abc"}, {value: 4, string: "def"}]
will be:
answers: {
1: {id: 1, value: 5, string: "abc"},
2: {id: 2, value: 4, string: "def"}
}
The Objects themselves can have nested "normalized arrays" as well.
For now I tried using mongoose type "Map" in the top-level-Schema like this:
answers: {
type: Map,
of: answer
}
Where "answer" is a separate mongoose.Schema itself.
But all I get is:
TypeError: Undefined type `Map` at `answers`
Did you try nesting Schemas? You can only nest using refs or arrays.
Why can't I just nest maps as expected? Is it even possible to project this "normalize array" structure in a mongoose schema, and if so, how?
Thank for reading!

Answer 1

I was in the same situation and it seems to work for me:
const ChildSchema = new Schema({
firstName: String,
});
const ParentSchema = new Schema({
name: String,
mapProperty: { type: Map, of: ChildSchema },
});
I do also get the validation triggered from mongoose on the ChildSchema so it seems to accept it just fine.
Hope it helps.