Explnation : how we can concate the time and sv . convert normalizaed the array stract
{
"data": [
{
"time": "1998-08-31T03",
"sv": {
"05": {
"13": 0,
"14": 1
}
}
}
]
}
For example expected document will be.
{
"data" : {
"1998-08-31T03:05:13Z": 0,
"1998-08-31T03:05:14Z": 1,
}
}
$reduce to iterate loop of data array$objectToArray convert sv object to key-value array$map to iterate loop of sv array$objectToArray convert minute object to key-value array$map to iterate loop of minutes array$concat to concat the required format of date parts$arrayToObject convert key-value pair to object$concatArrays to concat data elements$reduce to iterate loop of data array$reduce to iterate loop of nested data elements$mergeObjects to merge date objectsdb.collection.aggregate([
{
$project: {
data: {
$reduce: {
input: "$data",
initialValue: [],
in: {
$concatArrays: [
"$$value",
{
$map: {
input: { $objectToArray: "$$this.sv" },
as: "s",
in: {
$map: {
input: { $objectToArray: "$$s.v" },
as: "s1",
in: {
$arrayToObject: [
[
{
k: {
$concat: ["$$this.time", ":", "$$s.k", ":", "$$s1.k", "Z"]
},
v: "$$s1.v"
}
]
]
}
}
}
}
}
]
}
}
}
}
},
{
$project: {
data: {
$reduce: {
input: "$data",
initialValue: {},
in: {
$mergeObjects: [
"$$value",
{
$reduce: {
input: "$$this",
initialValue: {},
in: { $mergeObjects: ["$$value", "$$this"] }
}
}
]
}
}
}
}
}
])
db.collection.aggregate([
{
$unwind: "$data"
},
{
$addFields: {
"data.sv": {
$objectToArray: "$data.sv"
}
}
},
{
$unwind: "$data.sv"
},
{
$addFields: {
"data.sv.v": {
$objectToArray: "$data.sv.v"
}
}
},
{
$unwind: "$data.sv.v"
},
{
$addFields: {
"data": {
$arrayToObject: [
[
{
k: {
$concat: [
"$data.time",
":",
"$data.sv.k",
":",
"$data.sv.v.k",
"Z"
]
},
v: "$data.sv.v.v"
}
]
]
}
}
},
{
$group: {
_id: null,
data: {
$mergeObjects: "$data"
}
}
}
])