In Mongoose findOneAndUpdate, how can I make my post request work? - node.js

Question

Hi all so I am trying to make a post request that increments a value if it already exists and if not it should create a new item.
router.post('/', auth, async (req, res) => {
try {
const { name, price, image } = req.body;
var query = { name },
update = { $inc: { count: 1 } },
options = { upsert: true, new: true,};
await CartItem.findOneAndUpdate(query, update, options, function (
err,
data
) {
if (err) {
const newItem = new CartItem({
user: req.user.id,
name: name,
price: price,
image: image,
});
const item = newItem.save();
res.json(item);
} else {
res.json(data);
}
});
} catch (err) {
console.error(err.message);
res.status(500).send('Server Error');
}
});
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const CartItemSchema = new Schema({
user: {
type: Schema.Types.ObjectId,
ref: 'user',
},
name: {
type: String,
required: true,
},
price: {
type: Number,
required: true,
},
count: {
type: Number,
},
image: {
type: String,
required: true,
},
});
module.exports = CartItem = mongoose.model('cartItem', CartItemSchema);
So there are two problems here that I cannot wrap my head around(Pretty new with MongoDb, did do my research).
I can get the count to increment, but it increments with 2 or even more instead of 1. (I know other users also experienced this)
If the item is already in the cart(name matches) I want a new item to be added which does happen, but it only adds the name, count and Id. I want it to add the user, name, price and image.
Would appreciate some assistance.

Answer 1

you should create your document with a default value equals to 0.
define count at your schema like the following:
count: {
type: Number,
default: 0
}
then use { $inc: { <field1>: <amount1>, <field2>: <amount2>, ... } }.
link to docs: https://docs.mongodb.com/manual/reference/operator/update/inc/