Increment value in document and nested array simultaenously (with upsert) - mongodb

Question

I want to increment a value both on document root as well as inside a nested array.
A playground example here
The schema
const UserPoints = new Schema(
{
points: {
type: Number,
},
monthly: {
type: [
new Schema(
{
year: {
type: Number,
},
month: {
type: Number,
},
points: {
type: Number,
min: 0,
},
},
{
_id: false,
timestamps: false,
}
),
],
},
},
{
timestamps: false,
}
);
What I have tried
Variables used: (currentYear = 2021, currentMonth = 7, addPoints = 5)
Note: The year, month may not exist in the document yet, so I need to make it work with "upsert".
UserPoints.findOneAndUpdate(
{
_id: userId,
"monthly.year": currentYear,
"monthly.month": currentMonth,
},
{
$inc: {
points: addPoints,
"monthly.$.points": addPoints,
},
},
{
upsert: true,
new: true,
}
).exec()
This does not work. And gives out an error:
{
ok:0
code:2
codeName:"BadValue"
name:"MongoError"
}
I would appreciate if someone can point me at the right direction to increment these values in the same operation.
Update:
The only way that I could make it work is by first making a query to check if the (year, month) exists in the "monthly" array.
Depending if it exists, I either $push the new month, or $inc the existing one's values.

Answer 1

Pipeline update way, requires MongoDB >=4.2
You filter by _id using index, so it will be fast also.
Query
Test code here
(put id=1 will update(add points to member points and to externa point field), id=2 will do nothing,id=3 will insert the member to the empty array and update the points, id=4 will upsert with an array contains only this member,and the points its points)
Cases (this is the order checked in the $cond also)
document doesnt exists, array will have 1 single member, and root points will have the value of the new member points
document exists , member dont exists, monthly empty
adds the member {:year ...} and increases the root point field
document exists, member exists
increase points inside the member and the root point fields
document exists, member dont exist, monthly not empty
does nothing
db.collection.update({
"_id": 4
},
[
{
"$addFields": {
"isupsert": {
"$not": [
{
"$ne": [
{
"$type": "$monthly"
},
"missing"
]
}
]
}
}
},
{
"$addFields": {
"doc": {
"$switch": {
"branches": [
{
"case": "$isupsert",
"then": {
"_id": "$_id",
"points": 5,
"monthly": [
{
"year": 2021,
"month": 7,
"points": 5
}
]
}
},
{
"case": {
"$and": [
{
"$isArray": [
"$monthly"
]
},
{
"$eq": [
{
"$size": "$monthly"
},
0
]
}
]
},
"then": {
"_id": "$_id",
"points": 5,
"monthly": [
{
"year": 2021,
"month": 7,
"points": 5
}
]
}
}
],
"default": {
"$let": {
"vars": {
"found": {
"$not": [
{
"$eq": [
{
"$size": {
"$filter": {
"input": "$monthly",
"as": "m",
"cond": {
"$and": [
{
"$eq": [
"$$m.year",
2021
]
},
{
"$eq": [
"$$m.month",
7
]
}
]
}
}
}
},
0
]
}
]
}
},
"in": {
"$cond": [
"$$found",
{
"$mergeObjects": [
"$ROOT",
{
"points": {
"$add": [
"$points",
5
]
},
"monthly": {
"$map": {
"input": "$monthly",
"as": "m",
"in": {
"$cond": [
{
"$and": [
{
"$eq": [
"$$m.year",
2021
]
},
{
"$eq": [
"$$m.month",
7
]
}
]
},
{
"$mergeObjects": [
"$$m",
{
"points": {
"$add": [
"$$m.points",
5
]
}
}
]
},
"$$m"
]
}
}
}
}
]
},
"$$ROOT"
]
}
}
}
}
}
}
},
{
"$replaceRoot": {
"newRoot": "$doc"
}
},
{
"$unset": [
"isupsert"
]
}
],
{
"upsert": true
})

Answer 2

you should find in array by $elemMatch
UserPoints.findOneAndUpdate(
{
_id: userId,
"monthly":{$elemMatch:{"year": currentYear}},
"monthly":{$elemMatch:{"month": currentMonth}}
},
{
$inc: {
points: addPoints,
"monthly.$.points": addPoints,
},
},
{
upsert: true,
new: true,
}
).exec()