Mongodb update multiple documents with different values - node.js

Question

I have been trying to use updatemany with mongoose. I want to update the values in database using an array of objects.
[
{
"variantId": "5e1760fbdfaf28038242d676",
"quantity": 5
},
{
"variantId": "5e17e67b73a34d53160c7252",
"quantity": 13
}
]
I want to use variantId as filter.
Model schema is:
let variantSchema = new mongoose.Schema({
variantName: String,
stocks: {
type: Number,
min: 0
},
regularPrice: {
type: Number,
required: true
},
salePrice: {
type: Number,
required: true
}
})
I want to filter the models using variantId and then decrease the stocks.

Answer 1

As you need to update multiple documents with multiple criteria then .updateMany() wouldn't work - it will work only if you need to update multiple documents with same value, Try this below query which will help you to get it done in one DB call :
const Mongoose = require("mongoose");
let variantSchema = new mongoose.Schema({
variantName: String,
stocks: {
type: Number,
min: 0
},
regularPrice: {
type: Number,
required: true
},
salePrice: {
type: Number,
required: true
}
})
const Variant = mongoose.model('variant', variantSchema, 'variant');
let input = [
{
"variantId": "5e1760fbdfaf28038242d676",
"quantity": 5
},
{
"variantId": "5e17e67b73a34d53160c7252",
"quantity": 13
}
]
let bulkArr = [];
for (const i of input) {
bulkArr.push({
updateOne: {
"filter": { "_id": Mongoose.Types.ObjectId(i.variantId) },
"update": { $inc: { "stocks": - i.quantity } }
}
})
}
Variant.bulkWrite(bulkArr)
Ref : MongoDB-bulkWrite

Answer 2

I don't think this can be done with a single Model.updateMany query. You will need to loop the array and use Model.update instead.
for (const { variantId, quantity } of objects) {
Model.update({ _id: variantId }, { $inc: { stocks: -quantity } });
}
To run this in a transaction (https://mongoosejs.com/docs/transactions.html), the code should look something like this (however I have not tried or tested this):
mongoose.startSession().then(async session => {
session.startTransaction();
for (const { variantId, quantity } of objects) {
await Model.update({ _id: variantId }, { $inc: { stocks: -quantity } }, { session });
}
await session.commitTransaction();
});