I have the following mongoose schema

const groupSchema = new mongoose.Schema({
    club:{
        type: mongoose.Schema.Types.ObjectId,
        ref: 'Club',
        required:true,
    },
    group:[{
        team:{
            type: mongoose.Schema.Types.ObjectId,
            ref: 'Team',
            required:true,
        },
        wins:[{
            type: mongoose.Schema.Types.ObjectId,
            ref: 'Game',
            default:[],
        }],
        points:{
            type: Number,
            default: function(){
                return this.wins.length 
            }
        },
    }],
},{timestamps:true})

The issue that I am having is with the default value of the points attribute. It should return this.wins.lenght, but it allows returns 0.

When I tested it with this._id, it confirmed that I am referring to the right object as it was equal to the id of subdocument, yet it does not work with this.wins.length

any suggestions?