How to update a field using its previous value in MongoDB with updateOne

Question

I was trying to update the document with updateOne but got an error in code unable to access the previous value to update the field. getting type cast error. Using Mongoose version 7.0.1

invoiceSchema.updateOne({ appointmentId: convertIntoMongoId(invoiceDetail.appointmentId) },
                    {
                        $set: {
                            $inc: { pendingAmount: response.purchase_units[0].payments.captures[0].amount.value },
                            pendingAmount: { $subtract: ['$pendingAmount', response.purchase_units[0].payments.captures[0].amount.value] },
                            status: {
                                $cond: [
                                    {
                                        $and: [
                                            { $gt: ['$paidAmount', 0] },
                                            { $ne: ['$paidAmount', '$totalPayableAmount'] }
                                        ],


                                    },
                                    "Partially Paid",
                                    "Not Paid",
                                ]
                            }
                        }
                    }

                )
            }

{
    "error": {
        "error": {
            "stringValue": "\"{ '$subtract': [ '$pendingAmount', '15.00' ] }\"",
            "valueType": "Object",
            "kind": "Number",
            "value": {
                "$subtract": [
                    "$pendingAmount",
                    "15.00"
                ]
            },
            "name": "CastError",
            "message": "Cast to Number failed for value \"{ '$subtract': [ '$pendingAmount', '15.00' ] }\" (type Object) at path \"pendingAmount\""
        }
    },

}

Answer 1

You need to use Updates with Aggregation Pipeline. In short, wrap the $set stage in square brackets [] to denote an aggregation pipeline. This will turn $pendingAmount into the value of that field instead of the literal string $pendingAmount like so:

invoiceSchema.updateOne({ appointmentId: convertIntoMongoId(invoiceDetail.appointmentId) },
    [
        {
            $set: {
                $inc: { pendingAmount: response.purchase_units[0].payments.captures[0].amount.value },
                pendingAmount: { $subtract: ['$pendingAmount', response.purchase_units[0].payments.captures[0].amount.value] },
                status: {
                    $cond: [
                        {
                            $and: [
                                { $gt: ['$paidAmount', 0] },
                                { $ne: ['$paidAmount', '$totalPayableAmount'] }
                            ],


                        },
                        "Partially Paid",
                        "Not Paid",
                    ]
                }
            }
        }
    ]
);