Mongoose populate() - express

Question

referring to Mongoose url populate example given at https://mongoosejs.com/docs/populate.html#checking-populated , there seems to be a two way relationship between both Schema. What if I only have 1 way relationship for example ( using same schema example, But Person schema does not Story ref )
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const personSchema = Schema({
name: String,
age: Number
});
const storySchema = Schema({
author: { type: Schema.Types.ObjectId, ref: 'Person' },
title: String
});
const Story = mongoose.model('Story', storySchema);
const Person = mongoose.model('Person', personSchema);
How can I return a GET Story output that looks like the following :
{
author :{
name: "Bla bla bla",
age: 30
}
title : "ABC Story"
}
I am always getting this at the moment :
{
author :34235245453
title : "ABC Story"
}

Answer 1

I am not sure whether this is a good practise, but you can achieve this as follows
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const personSchema = Schema({
name: String,
age: Number
});
const storySchema = Schema({
author: Schema.Types.ObjectId, //modified by just defining the type
title: String
});
const Story = mongoose.model('Story', storySchema);
const Person = mongoose.model('Person', personSchema);
when populating,
SOMETHING.find()
.populate({
'path':'author',
'model':'Person'
});

Answer 2

I think you are confusing populated() function and populate() function.
To be able to retrieve the author info of a story, we need to use populate like this:
router.get("/stories/:id", async (req, res) => {
const result = await Story.findById(req.params.id).populate("author");
res.send(result);
});
Let's say we have this person:
{
"_id": "5e3c63ba3a178830dc497a00",
"name": "Name1",
"age": 33,
"__v": 0
}
And this story by user:
{
"_id": "5e3c63e93a178830dc497a02",
"author": "5e3c63ba3a178830dc497a00",
"title": "Story1",
"__v": 0
}
The result will be like this when we send a get request to our route ( http://.../stories/5e3c63f33a178830dc497a02)
{
"_id": "5e3c63e93a178830dc497a02",
"author": {
"_id": "5e3c63ba3a178830dc497a00",
"name": "Name1",
"age": 33,
"__v": 0
},
"title": "Story1",
"__v": 0
}
To get all stories with author info, we can use find() method like this:
router.get("/stories", async (req, res) => {
const result = await Story.find().populate("author");
res.send(result);
});