How to make a record in mongodb refrence model - node.js

Question

I working on Mongoose and Express project where by I have 3 models: User, Album and Purchase. The purchase model references the user and album. I am creating a POST endpoint where by I can make a purchase and then retrieve the data as well as the user and album relations which should be populated with their data, but I am stuck.
var app = express();
var bodyParser = require('body-parser');
var mongoose = require('mongoose');
var userSchema = mongoose.Schema({
// TODO: Define Schema
name: {
type: String,
required: true
}
})
var User = mongoose.model('User', userSchema)
var albumSchema = mongoose.Schema({
// TODO: Define Schema
title: {
type: String,
required: true
},
performer: {
type: String,
required: true
},
cost: {
type: Number,
required: true
}
})
var Album = mongoose.model('Album', albumSchema);
var puchaseSchema = mongoose.Schema({
// TODO: Define Schema
user: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Album'
},
album: {
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
}
})
var Purchase = mongoose.model('Purchase', puchaseSchema);
app.use(bodyParser.json());
app.listen(3000);
// TODO: GET /albums
app.get('/albums', (req,res) => {
Album.find()
.then((response) => {
res.json({data: response})
})
.catch(err => {
res.json({error: err})
})
})
// TODO: GET /albums/:id
app.get('/albums/:id', (req,res) => {
Album.findById(req.params.id)
.then(response => {
res.json({data: response})
.catch(err => {
res.json({Error: err})
})
})
})
// TODO: POST /albums
app.post('/albums', (req,res) => {
const newPost = Album({
title: req.body.title,
performer: req.body.performer,
cost: req.body.cost
})
newPost.save(err => {
if(err)
res.json({error: err})
})
.then(data => {
res.json({data: data})
})
})
// TODO: PUT /albums/:id
app.put('/albums/:id', (req,res) => {
Album.findByIdAndUpdate(req.params.id, req.body, {new: true},
(err, album) =>{
if(err) return res.status(500).send(err)
return res.json({data: album})
})
})
// TODO: DELETE /albums/:id
app.delete('/albums/:id', (req,res) => {
const id = req.params.id
Album.findById(id)
.then(docs => {
docs.remove()
res.status(204)
.json({data:docs})
})
})
// TODO: POST /purchases
app.post('/purchases', (req,res) => {
})```

Answer 1

This might help you. Look into mongoose's populate method.
app.post('/purchases', (req,res) => {
const user = req.body.userId;
const album = req.body.albumId;
const newPurchase = new Purchase({
user: user,
album: album
});
newPurchase.save().then((purchase) => {
Purchase.findById(purchase.id).populate('user').populate('album').then((purchaseData) => {
return res.json({purchaseData});
}).catch(e => {
console.log(e);
});
}).catch(e => {
console.log(e);
});
})
Here's an alternative for populating after saving the document.
app.post('/purchases', (req,res) => {
const user = req.body.userId;
const album = req.body.albumId;
const newPurchase = new Purchase({
user: user,
album: album
});
newPurchase.save().then((purchase) => {
Purchase.populate(purchase, [{path: 'user'}, {path: 'album'}], (err, data) => {
if(err) {
return res.json(e);
}
return res.json(data);
});
}).catch(e => {
console.log(e);
});
}
)
As mentioned here: https://mongoosejs.com/docs/api.html#model_Model.populate