Problem with adding an item to an array of mongoose reference objects - arrays

Question

In my NodeJS and MongoDB app, I have 2 mongoose schemas:
companySchema:
const companySchema = new Schema({
name: {
type: String,
required: true
},
products: [{
type: Schema.Types.ObjectId,
ref: 'Product',
required: false
}]
});
companySchema.statics.addProduct = function (productId) {
let updatedProducts = [...this.products];
updatedProducts.push(productId);
this.products = updatedProducts;
return this.save();
}
module.exports = mongoose.model(‘Company’, companySchema);
productSchema:
const productSchema = new Schema({
name: {
type: String,
required: true
},
quantity: {
type: Number,
required: true
}
});
module.exports = mongoose.model('Product', productSchema);
Every time I add a new product to productSchema, I would like to add the _id of the newly created product to products array in companySchema in order to easily access products later on.
To accomplish this, I wrote:
const Company = require('../models/company');
const Product = require('../models/product ');
exports.postAddProduct = (req, res, next) => {
const name = req.body.name;
const quantity = req.body.quantity;
const product = new Product({
name: name,
quantity: quantity
});
product.save()
.then(product => {
return Company.addProduct(product._id);
})
.then(result => {
res.redirect('/');
})
.catch(err => console.log(err));
}
I am getting an error: TypeError: this.products is not iterable.

Answer 1

You are setting a static method, which is a method on the model rather than the document instance.
Therefore, this refers to the model itself, not the individual document.
Unlike the document, the model doesn’t have an array (iterable) called products so it can’t be spread into a new array.
Try using methods instead of statics:
companySchema.methods.addProduct = function (productId) {
...
}
I hope this helps.