Maintain order as original document while using addToSet in MongoDb - mongodb

Question

I read the documentation and found that addToSet doesn't guarantee order.
But is there any way I can preserve the order as the original document.
My Query is :-
aggregate([{$match: {
$or:[{"Name.No":"119"},{"Name.No":"120"}]
}}, {$project: {
x:{$objectToArray:"$Results"}
}},{$unwind: "$x"},{$group: {_id: "$x.k", distinctVals: {$addToSet: "$x.v.TCR"}}}])
Sample Data:
{"Name" : {"No." : "119","Time" : "t"},
"Results":{"K1" : {"Counters" : x, "TCR" : [{"Name" : "K11", "Result" : "PASSED"},
{"Name" : "K12","Result" : "FAILED"},
{"Name" : "K13","Result" : "PASSED"}]
},
"K2" : {"Counters": y, "TCR" : [{"Name" : "K21","Result" : "PASSED"},
{"Name" : "K22","Result" : "PASSED"}]
}
}
}
}
Job2;
{"Name" : {"No." : "120","Time" : "t1"},
"Results":{"K1" : {"Counters" : x, "TCR" : [{"Name" : "K11", "Result" : "PASSED"},
{"Name" : "K12","Result" : "PASSED"},
{"Name" : "K13","Result" : "FAILED"}]
},
"K3" : {"Counters": y, "TCR" : [{"Name" : "K31","Result" : "PASSED"},
{"Name" : "K32","Result" : "PASSED"}]
}
}
}
Expected;
{"Name" : {"No." : "119-120","Time" : "lowest(t,t1)"},
"Results":{"K1" : {"Counters" : x, "TCR" : [{"Name" : "K11", "Result" : "PASSED"},
{"Name" : "K12","Result" : "PASSED"},
{"Name" : "K13","Result" : "PASSED"}]
},
"K2" : {"Counters": y, "TCR" : [{"Name" : "K21","Result" : "PASSED"},
{"Name" : "K22","Result" : "PASSED"}]
},
"K3" : {"Counters": y, "TCR" : [{"Name" : "K31","Result" : "PASSED"},
{"Name" : "K32","Result" : "PASSED"}]
}
}
}
I want to maintain the order same as original document, also every time document would change,so I cant sort based on any parameter.

Answer 1

convert Results object to array format using $objectToArray
$unwind deconstruct Results array
$unwind deconstruct Results.v.TCR array
$match to filter PASSED Result
$group by Results.k and get first Name, get first Counters, construct array of Results.v.TCR
$group by null and get minimum Time, construct unique array of No, construct Results array in key-value pair, $reduce to iterate loop of TCR and remove duplicate documents
$project to show required fields, convert Results array to object using $arrayToObject, convert No array to string and concat with "-"
db.collection.aggregate([
{ $addFields: { Results: { $objectToArray: "$Results" } } },
{ $unwind: "$Results" },
{ $unwind: "$Results.v.TCR" },
{ $match: { "Results.v.TCR.Result": "PASSED" } },
{
$group: {
_id: "$Results.k",
Name: { $first: "$Name" },
Counters: { $first: "$Results.v.Counters" },
TCR: { $push: "$Results.v.TCR" }
}
},
{
$group: {
_id: null,
Time: { $min: "$Name.Time" },
No: { $addToSet: "$Name.No" },
Results: {
$push: {
k: "$_id",
v: {
Counters: "$Counters",
TCR: {
$reduce: {
input: "$TCR",
initialValue: [],
in: {
$cond: [
{
$in: [
{
Name: "$$this.Name",
Result: "$$this.Result"
},
"$$value"
]
},
"$$value",
{
$concatArrays: [
"$$value",
[
{
Name: "$$this.Name",
Result: "$$this.Result"
}
]
]
}
]
}
}
}
}
}
}
}
},
{
$project: {
_id: 0,
Results: { $arrayToObject: "$Results" },
Name: {
Time: "$Time",
No: {
$reduce: {
input: "$No",
initialValue: "",
in: {
$concat: [
"$$value",
{ $cond: [{ $eq: ["$$value", ""]}, "", "-"] },
"$$this"
]
}
}
}
}
}
}
])
Playground
The "." (dot) in "No." field is not valid, it may cause issue in mongodb query operations, i would suggest do not use "." (dot) as field name.