How to implement an Array with objects in Schema Mongoose?

Question

JavaScript

How to implement an Array with objects in Schema Mongoose so that there are no cast errors?
I tried a lot, the result was getting the desired one, but immediately after the result, a CastError error occurred. Mongoose Schema Mongoose

entry example . There is immediately more a question of what to enter here, and not what I entered and it didn’t work out for me : And when I tried my attempts, I got a casterror error I tried to do friends: [{ }],friends: [{ user: String }],friends: [{ _id: false,user:String}] , nothing helped, I don't know what to do anymore

Answer 1

friends: [
    {
      id: { type: String, required: true, unique: true },
    },
],