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Mongodb findOneAndUpdate() compare sums of date and timestamps

I'm working on a MongoDB (+mongoose) based scheduler where tasks have the following type
TaskSchema {
running: Boolean
executedAt: Date,
next: Number (millisecond)
}
I wish to fetch Tasks which should be executed meaning the sum of executedAt + next < now
Since the scheduler should lock the Task, the running flag should be flipped to true in the same operation, hence I'm using findOneAndUpdate()
I'm stuck at dealing with the sum of executedAt and next. How would one compare the sum of these to new Date/Date.now() ?
When doing an aggregation one could use $dateAdd from what I understand so in a find query could be something. like the following:
Task.find({
$and: [
{ running: { $ne: null } },
{ running: false },
{ next: { $ne: null } },
{ executedAt: { $ne: null } },
{
$expr: {
$lt: [
{
$dateAdd: {
startDate: '$executedAt',
unit: 'millisecond',
amount: '$next',
},
},
new Date().toUTCString(),
],
},
},
],
})
However this does not work.

Apparently, my initial attempt works and the above query is nearly correct. Since I didn't set the $addDate timezone explicitly I tried making the new Date() a UTC string. Considering #Wernfrieds comment this complies to my requirements:
Task.find({
$and: [
{ running: { $ne: null } },
{ running: false },
{ next: { $ne: null } },
{ executedAt: { $ne: null } },
{
$expr: {
$lt: [
{
$dateAdd: {
startDate: '$executedAt',
unit: 'millisecond',
amount: '$next',
},
},
new Date(),
],
},
},
],
})

pass mongo dollar sign aggregation var to date object in javascript

im trying to perform this aggregation in a mongo $lookup operation where i want to pass a variable down to a date object.
Wondering if this is possible
deal_cliff: new Date(new Date("$integrated").getTime() + 540 * 86400000),
as you can tell the problem is that "$integrated" is being used as a string and not an actual date since its a mongo dollar sign var.
any kind of help would be appreciated.
full code:
$lookup: {
from: 'deals',
// set variables that can be used in the pipeline below
let: {
group_id: '$parentGroupId',
internal_comm: { $toDecimal: '$internalCommission.amount' },
dealer_id: dealerId,
deal_cliff: new Date(new Date('$integrated').getTime() + 540 * 86400000), <---- Problem here
booking_provider: '$provider',
booking_booked_on: '$bookedOn'
},
pipeline: [
{
$match: {
$expr: {
$eq: ['$groupId', '$$group_id']
}
}
},
{ $unwind: '$dealers' },
...(userType === USER_TYPES.BDM && dealerId
? [
{
$match: {
$expr: {
$eq: ['$dealers.dealerId', '$$dealer_id']
}
}
}
]
: []),
{
$addFields: {
dealerComm: {
$cond: [
// If booking provider not Trivago & booking <= cliff date
{
$and: [
{ $ne: ['$$booking_provider', "Trivago"] },
{ $lte: ['$$booking_booked_on', "$$deal_cliff"] }
]
},
// do
{
$multiply: [
'$dealers.effort',
'$$internal_comm',
'$dealers.repCommission'
]
},
// else return
0
]
}
}
},
{
$group: {
_id: '$_id',
totalDealerComm: {
$sum: {
$cond: {
if: '$dealerComm',
then: { $toDecimal: '$dealerComm' },
else: 0
}
}
}
}
}
],
as: 'deal'
}

How to get last defined value in an aggregration in MongoDB?

I have a collection in which the documents sometimes contain a status field and sometimes don't. There is always a data field. I'm trying to form a query to get the latest value for both, but when using the $last operator, I get the values from the latest document and results in status sometimes being null. How can I get it to retrieve the latest defined status value, while still keeping the data value from the latest document?
Current aggregration:
const project = await collection.aggregate([
{
$match: {
projectId: id
}
},
{
$group: {
_id: '$projectId',
status: {
$last: '$status'
},
data: {
$last: '$data'
}
}
}
]).toArray();

You can use $facet and perform multiple query in the parallel on the same set of documents.
db.collection.aggregate([
{
$facet: {
last_status: [
{
"$match": {
status: {
$ne: null
}
}
},
{
"$sort": {
_id: -1
}
},
{
"$limit": 1
}
],
last_data: [
{
"$match": {
data: {
$ne: null
}
}
},
{
"$sort": {
_id: -1
}
},
{
"$limit": 1
}
]
}
},
{
"$project": {
other_fields: {
$first: "$last_data"
},
status: {
$first: "$last_status.status"
}
}
}
])
Working example

How to work with date conditions using mongodb query operators?

I have a mongo db model with the name DrSlots. One of the fields in the model is slots which is as follows
slots: [
{
slot: {
start: {
type: Date,
},
end: {
type: Date,
},
},
status: {
type: String,
},
},
],
Now I want to find the slots based on certain conditions. Firstly the start time should be greater or equal to the start time provided by the user and the end time should be lesser or equal to the end time provided by the user in the same document. For this reason, I wrote the following query which for some reason is not executing correctly.
const slots = await DrSlots.findOne({
$and: [
{ doctor: req.params.doctorId },
{ dateOfAppointment: params.date },
{
"slots.slot": {
start: { $gte: params.start },
end: { $lte: params.end },
},
},
],
});
I am not getting correct results.
Secondly I also want to implement that if params.start or params.end is not provided by user, the query should not check it. How would i implement this? TIA

In order to find the slots between start and end, you could use $elemMatch and do the following:
$and: [
...,
{
slots: {
$elemMatch: {
start: { $gte: params.start },
end: { $lte: params.end },
}
}
}
]
As also pointed out by #Taplar in the comments.
Reference: https://docs.mongodb.com/manual/reference/operator/query/elemMatch/

// You can make query using some condition basis.
let query = [
{ doctor: req.params.doctorId },
{ dateOfAppointment: params.date }
];
// and after that check params.start and params.end values
if (params.start && params.end) {
query.push({
"slots.slot": {
$elemMatch: {
start: { $gte: params.start },
end: { $lte: params.end },
}
}
})
}
const slots = await DrSlots.findOne({
$and: query
});

mongoose recursively find elements in db

I am writing a query to find 'n' no of videos from collection. I have set primary , secondary and tertiary language set of the user(Suppose Tamil(P), Hindi(S), English(t)). I want to first find the videos of primary language, if returns videos are less then 'n' then search from secondary language and last from tertiary language. If at any stage n videos are found then no need to search further. I am from c background, so I am thinking to use recursion, but is there any method that I can find videos in one query.

you could do it like this assuming the number of languages is static.
var langs = ['hindi', 'tamil', 'english']; //arrange the languages in the priority you want
var limit = 5;
db.videos.aggregate(
[
{
$group: {
_id: null,
vids: {
$push: '$$ROOT'
}
}
},
{
$project: {
vids: {
$concatArrays: [
{
$slice: [
{
$filter: {
input: "$vids",
cond: { $eq: ["$$this.language", langs[0]] }
}
}, limit
]
},
{
$slice: [
{
$filter: {
input: "$vids",
cond: { $eq: ["$$this.language", langs[1]] }
}
}, limit
]
},
{
$slice: [
{
$filter: {
input: "$vids",
cond: { $eq: ["$$this.language", langs[2]] }
}
}, limit
]
}
]
}
}
},
{
$unwind: '$vids'
},
{
$replaceWith: '$vids'
},
{
$limit: limit
}
])
make sure to add an index on the language field.