Mongo DB - add date to reference object - mongodb

Question

I am using mongoose and have two schemas, user and community:
UserSchema:
const UserSchema = new Schema({
name: String,
communities: [{ type: Schema.Types.ObjectId, ref: CommunityModel }],
}, { timestamps: true });
}
Community:
const CommunitySchema = new Schema({
name: String,
users: [
{ type: Schema.Types.ObjectId, ref: "User" }
]
}, { timestamps: true });
When user joins a community, I want to know when it happened, so I'd like to add a joinedAt or createdAt to each community in the UserSchema. How could I achieve it if it is a reference? Is it possible? And if not, what could be the alternative?
Thanks!

Answer 1

This is the correct answer:
AI solved it for me, here is the correct example:
import * as mongoose from 'mongoose';
const Schema = mongoose.Schema;
interface User {
name: string;
email: string;
communities: Community[];
}
interface Community {
name: string;
description: string;
users: User[];
}
const userSchema = new Schema({
name: String,
email: String,
}, {
timestamps: true,
});
const communitySchema = new Schema({
name: String,
description: String,
}, {
timestamps: true,
});
// Define the user_communities table using the communitySchema
const userCommunitySchema = new Schema({
user: { type: Schema.Types.ObjectId, ref: 'User' },
community: { type: Schema.Types.ObjectId, ref: 'Community' },
joined_on: Date,
}, {
timestamps: true,
});
// Use the userCommunitySchema to create the UserCommunity model
const UserCommunity = mongoose.model('UserCommunity', userCommunitySchema);
// Use the userSchema to create the User model, and define a virtual property
// for accessing the user's communities
userSchema.virtual('communities', {
ref: 'Community',
localField: '_id',
foreignField: 'user',
justOne: false,
});
const User = mongoose.model<User>('User', userSchema);
// Use the communitySchema to create the Community model, and define a virtual property
// for accessing the community's users
communitySchema.virtual('users', {
ref: 'User',
localField: '_id',
foreignField: 'community',
justOne: false,
});
const Community = mongoose.model<Community>('Community', communitySchema);
The userSchema and communitySchema are then used to create the User and Community models, respectively. For the User model, a virtual property called communities is defined using the virtual method. This virtual property is used to specify how to populate the user.communities property when querying the database. The communitySchema also defines a users virtual property, which is used to populate the community.users property when querying.