MongoDB NodeJS - How to get sum of values between two dates? - node.js

Question

I have the below code snippet which will retrieve Date and count from a MongoDb collection from a specific date. Example: Retrieve date, count from 05-05-2020.
||Date||Count||
|05-06-2020|4|
|05-07-2020|25| and so on.
i want to add another logic to retrieve aggregate sum of 7 days instead of individual dates. Appreciate any help.
mongoClient.db().collection(COLLECTION.AUDIT).aggregate([
{
$match: { created_at: { $gt: date } }
},
{
$group: {
_id: {
$dateToString: { format: "%Y-%m-%d", date: "$created_at" }
},
count: { $sum: 1 }
}
},
{
$sort: { "_id": -1 }
}
])

Answer 1

The simplest way to do what I think you're asking would be to transform your group operator to $week instead of $dateToString. Since a week is 7 days, this will group all the documents from the same week, and return a count of the documents, along with the number of the week. To get both results from 1 query, combine them into a facet. So:
mongoClient.db().collection(COLLECTION.AUDIT).aggregate([
{
$match: { created_at: { $gt: date } }
},
{
$facet: {
by_week: {
$group: {
_id: { $week: $created_at},
count: { $sum: 1 }
},
{ $sort: { "_id": -1 }}
},
by_day: {
$group: {
_id: {
$dateToString: { format: "%Y-%m-%d", date: "$created_at" }
},
count: { $sum: 1 }
}
},
{ $sort: { "_id": -1 }}
}
},
])