I want to increment the quantity field inside the products array of the cart when the productId matches to the itemid. Also I want to get the updated document in return.

Here is my Cart Model

import mongoose from 'mongoose';

const cartSchema = new mongoose.Schema({
    userId: {
        type: String,
        required: true,
    },
    products: [
        {
            productId: {
                type: String,
            },
            quantity: {
                type: Number,
                default: 1
            }
        }

    ]
    
}, {timestamps: true});
const Cart = new mongoose.model('Cart', cartSchema);

export default Cart;

and here is what I m doing:

const updatedCart = await Cart.findOneAndUpdate({"products.productId": itemid}, {$inc: {quantity: 1}}, {new: true})

//console.log(updatedCart)

But an empty array return and also quantity didn't increment.

CodePudding user response：

As from your schema, there is no quantity field. Hence your mongoose operation is not updating any document.

Hence it will not return any document as new: true only returns the updated document.

[options.returnOriginal=null] «Boolean» An alias for the new option. returnOriginal: false is equivalent to new: true.

You can use positional $ operator to update the quantity of filtered product in products array.

The positional $ operator identifies an element in an array to update without explicitly specifying the position of the element in the array.

const updatedCart = await Cart.findOneAndUpdate({ "products.productId": itemid },
  { $inc: { "products.$.quantity": 1 } }, 
  { new: true });

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