Add Data to MongoDB Models At Different Times - node.js

Question

I have a pretty good understanding of mongdoDB with mongoose, but this one aspect of it has been confusing me for a while now. I have a user.js model with a username, password, etc (all the basic user stuff). This data is added when a user registers for an account. But each user also has more data linked to it that IS NOT created or added at the time of registering.
This is my model:
// User Schema
const UserSchema = new Schema({
// PERSONAL USER INFO
username: {
type: String,
index: true
},
email: {
type: String
},
password: {
type: String
},
// INSTAGRAM ACCOUNT INFORMATION
ig_username: {
type: String
},
ig_password: {
type: String
},
story_price: {
type: Number
},
fullpost_price: {
type: Number
},
halfpost_price: {
type: Number
},
leads: [{
title: { type: String }
}]
});
// EXPORTS
const User = module.exports = mongoose.model('user', UserSchema);
All the field except "leads" are created at the time of registering. But I want to fill the Leads field using another form. I've tried the .update(), .save(), $set, $push, and all kinds of methods, but I cannot get it to work.
Most solutions that I have found use var user = new User({...}) to create a new user and then use .save() after adding the additional data. But this seems wrong since the user has already been created and I am just trying to add data to an additional field.
I think I'm just glossing over something basic, but if there is a way to do this I would be glad to hear it. Thanks!

Answer 1

I would create a sub-schema for leads
// Create a sub-schema for leads
const leadsSubSchema = new Schema({
title: {
type: String,
},
});
// Create a schema for user
const UserSchema = new Schema({
username: {
type: String,
index: true
},
// ...
leads: [leadsSubSchema]
});
// EXPORTS
const User = module.exports = mongoose.model('user', UserSchema);
Then for the update
User.update({
_id: user_id,
}, {
$push: {
leads: lead_to_add,
},
});