Mongoose : update object in array (bulkwrite) - node.js

Question

i'm trying to update a object in array.
My field wasn't an array before, i used to use this code to update my field :
exports.updateStock = (req, res, next) => {
console.log(req.body.order.products);
let myOperations = req.body.order.products.map((prod) => {
return {
updateOne: {
filter: { _id: prod._id },
update: { $inc: { stock: -prod.quantity, sold: +prod.quantity } },
},
};
});
Product.bulkWrite(myOperations, {}, (err, products) => {
if (err) {
console.log("im here", err);
return res.status(400).json({
error: "Bulk operation failed",
});
}
next();
});
};
field :
stock: [
{
size: {
type: String,
required: true,
},
stock: {
type: Number,
required: true,
},
},
],
any idea how i can update my stock.stock based on size?
the size is passed with product -> prod.size
Example :
in store i have size : M | 100 stocks
L | 150 stocks
XS| 10 stocks
user : want to buy size M and quantity 2
so after the order i have to update Size m stocks
100-2 = 98 stocks remaing after order :
M | 98 stocks
L | 150 stocks
XS| 10 stocks
My entire product schema :
const mongoose = require("mongoose");
const { ObjectId } = mongoose.Schema;
const productSchema = new mongoose.Schema(
{
name: {
type: String,
trim: true,
required: true,
maxlength: 32,
},
description: {
type: String,
trim: true,
required: true,
maxlength: 2000,
},
discountprice: {
type: Number,
maxlength: 32,
trim: true,
},
price: {
type: Number,
required: true,
maxlength: 32,
trim: true,
},
category: [
{
type: ObjectId,
ref: "Category",
required: true,
},
],
subcategory: [
{
type: ObjectId,
ref: "SubCategory",
required: true,
},
],
stock: [
{
size: {
type: String,
required: true,
},
stock: {
type: Number,
required: true,
},
},
],
sold: {
type: Number,
default: 0,
},
photo: [String],
},
{ timestamps: true }
);
module.exports = mongoose.model("Product", productSchema);

Answer 1

You can use arrayfilters to update stock on the base of size in array stock,
updateOne: {
filter: { _id: prod._id },
update: { $inc: { "stock.$[elem].stock": -prod.quantity, sold: +prod.quantity } },
arrayFilters: [{ "elem.size": prod.size }]
}