Accessing child methods in parent for mongoose succeeds in array and fails with single child - node.js

Question

UPDATE : Solution is at bottom of question
I have an express site using mongoose.
I'll greatly simplify to say that I have adults, kids, and house models. When I create methods on kids, I can call them from within methods on adults and get a result. I can also call them from my .ejs views. However, when I create methods on house, I can only get a result from my .ejs views and get undefined when called from within methods on adults. Example code follows.
adult.js
const mongoose = require('mongoose');
const adultSchema = mongoose.Schema({
name: { type: String },
size: {type: String},
kids: [{type: mongoose.Schema.Types.ObjectId, ref: 'Kid', required: true}]
house:{type: mongoose.Schema.Types.ObjectId, ref: 'House', required: true}
});
adultSchema.method({
getKidsDescription: function() {
if (this.kids.length < 1) {
return 'No kids yet';
} else {
let ev = 'Kids, aged: ';
let kds = this.kids;
kds.forEach(function(k){
ev = ev + 'k.getAge()' // works
})
return ev;
}
},
getHouseDescription: function(){
return 'A fabulous house on '+this.house.getFullStreet(); // does not work
}
})
module.exports = mongoose.model('Adult', adultSchema);
kid.js
const mongoose = require('mongoose');
const kidSchema = mongoose.Schema({
name: { type: String },
size: {type: String},
birthdate: {type:Date}
});
kidSchema.method({
getAge: function() {
return (Math.floor(new Date() - this.birthdate)/(1000*60*60*24*365))
},
})
module.exports = mongoose.model('Kid', kidSchema);
house.js
const mongoose = require('mongoose');
const houseSchema = mongoose.Schema({
name: { type: String },
city: {type: String},
street: {type:String}
});
houseSchema.method({
getFullStreet: function() {
return this.street + ' Road';
},
})
module.exports = mongoose.model('House', houseSchema);
When I make a query for theAdult, it looks like this:
controller.js
exports.main = async (req, res, next) => {
if (req.theAdult) {
try {
const found = await db.fetchAdult(req.theAdult._id)
res.render('/main', {
//theHouse: found.house //below I show this working
});
} catch(e) {
throw new Error(e.message)
}
} else {
res.redirect('/');
}
}
db.js
exports.fetchAdult = (id) => {
return Adult.findById(id)
.populate({ path: 'kids'})
.populate({ path: 'house'})
.exec()
.then(doc => {
return doc;
});
}
Assuming house is passed to view as an object when rendered (commented out above), this works
view.ejs
<p> <%= theHouse.getFullStreet() %></p>
Assuming house populated on the call to load the Adult, this returns undefined.
view.ejs
<p> <%= theAdult.house.getFullStreet() %></p>
At the same time, both of these work
view.ejs
<ul> <% theAdult.kids.forEach(function(k) { %>
<li><%= k.getAge() %> </li>
<% }); %>
</ul>
<p> <% theAdult.getKidsDescription() %> </p>
What I am not understanding is how the method calls work for objects in array and work in the view but do not work for objects on in an array. This is a single child error (for me). If it did not work in the view, I would assume that the method getFullStreet() was the problem, but it works in the view. If the array methods could not be called within the parent, I would assume the issue was with trying to access getFullStreet() in the parent.
What am I missing?
SOLUTION
I was fetching theAdult in my call to show view.ejs, but I was then actually relying on currentAdult which referred to req.adult and did not have the fields populated. My solution was to add a pre hook to the adult schema that always populates house on find.
in adult.js
adultSchema.pre('find', function() {
this.populate('house')
})

Answer 1

Have you tried passing a hydrated theAdult? It might only see the ObjectID, without any other data or methods.