multiple updates for an array with $push - node.js

Question

consider the following document skeleton
{
_id: "615749dce3438547adfff9bc",
items: [
{
type: "shirt",
color: "red",
sizes: [
{
label: "medium",
stock: 10,
price: 20,
},
{
label: "large",
stock: 30,
price: 40,
}
]
},
{
type: "shirt",
color: "green",
sizes: [
{
label: "small",
stock: 5,
price: 3,
},
{
label: "medium",
stock: 5,
price: 3,
},
]
}
]
}
when a new item comes in, I want to insert a new document to items, unless an item exists with the same type and color as the new one, in this case I want only to merge sizes into that existing item's sizes.
sizes does not have to be unique.
I tried to use $push with upsert: true and arrayFilters but apparently $push ignores arrayFilters.
node with mongodb package.

Answer 1

Query1
filter to see if exists
if exists map to update, else add in the end
*2 array reads, but stil faster than query2
Test code here
db.collection.update({},
[
{
"$set": {
"newitem": {
"type": "shirt",
"color": "red",
"sizes": [
{
"label": "medium"
}
]
}
}
},
{
"$set": {
"found": {
"$ne": [
{
"$filter": {
"input": "$items",
"cond": {
"$and": [
{
"$eq": [
"$$this.type",
"$newitem.type"
]
},
{
"$eq": [
"$$this.color",
"$newitem.color"
]
}
]
}
}
},
[]
]
}
}
},
{
"$set": {
"items": {
"$cond": [
{
"$not": [
"$found"
]
},
{
"$concatArrays": [
"$items",
[
"$newitem"
]
]
},
{
"$map": {
"input": "$items",
"in": {
"$cond": [
{
"$and": [
{
"$eq": [
"$$this.type",
"$newitem.type"
]
},
{
"$eq": [
"$$this.color",
"$newitem.color"
]
}
]
},
{
"$mergeObjects": [
"$$this",
{
"sizes": {
"$concatArrays": [
"$$this.sizes",
"$newitem.sizes"
]
}
}
]
},
"$$this"
]
}
}
}
]
}
}
},
{
"$unset": [
"found",
"newitem"
]
}
])
Query2
(alternative solution)
reduce and do the update
if found keep the updated, else add in the end
*1 array read (but concat is slow, for big arrays, >500 members, if you have big arrays use query1)
*this is the normal way to do it, if we had a fast way to add in the end of the array, but we dont, so Query1 is faster
Test code here
db.collection.update({},
[
{
"$set": {
"newitem": {
"type": "shirt",
"color": "red",
"sizes": [
{
"label": "medium"
}
]
}
}
},
{
"$set": {
"items-found": {
"$reduce": {
"input": "$items",
"initialValue": {
"items": [],
"found": null
},
"in": {
"$cond": [
{
"$and": [
{
"$eq": [
"$$value.found",
null
]
},
{
"$eq": [
"$$this.type",
"$newitem.type"
]
},
{
"$eq": [
"$$this.color",
"$newitem.color"
]
}
]
},
{
"items": {
"$concatArrays": [
"$$value.items",
[
{
"$mergeObjects": [
"$$this",
{
"sizes": {
"$concatArrays": [
"$$this.sizes",
"$newitem.sizes"
]
}
}
]
}
]
]
},
"found": true
},
{
"items": {
"$concatArrays": [
"$$value.items",
[
"$$this"
]
]
},
"found": "$$value.found"
}
]
}
}
}
}
},
{
"$set": {
"items": {
"$cond": [
"$items-found.found",
"$items-found.items",
{
"$concatArrays": [
"$items-found.items",
[
"$newitem"
]
]
}
]
}
}
},
{
"$unset": [
"items-found",
"newitem"
]
}
])