How to aggregate fields from embedded documents in Mongoose - node.js

Question

Coverage Model.
var CoverageSchema = new Schema({
module : String,
source: String,
namespaces: [{
name: String,
types: [{
name: String,
functions: [{
name: String,
coveredBlocks: Number,
notCoveredBlocks: Number
}]
}]
}]
});
I need coveredBlocks aggregations on every level:
*Module: {moduleBlocksCovered}, // SUM(blocksCovered) GROUP BY module, source
**Namespaces: [{nsBlocksCovered}] // SUM(blocksCovered) GROUP BY module, source, ns
****Types: [{typeBlocksCovered}] // SUM(blocksCovered) BY module, source, ns, type
How do I get this result with Coverage.aggregate in Mongoose ?
{
module: 'module1',
source: 'source1',
coveredBlocks: 7, // SUM of all functions in module
namespaces:[
name: 'ns1',
nsBlocksCovered: 7, // SUM of all functions in namespace
types:[
{
name: 'type1',
typeBlocksCovered: 7, // SUM(3, 4) of all function in type
functions[
{name: 'func1', blocksCovered: 3},
{name:'func2', blocksCovered: 4}]
}
]
]
}

Answer 1

My ideas is to deconstruct everything using $unwind then reconstruct the document back again using group and projection.
aggregate flow:
//deconstruct functions
unwind(namesapces)
unwind(namespaces.types)
unwind(namespace.types.functions)
//cal typeBlocksCovered
group module&source ,ns,type to sum functions blocksCovered->typeBlocksCovered + push functions back to types
project to transform fields to be easier for next group
// cal nsBlocksCovered
group module&source ,ns to sum typeBlocksCovered -> nsBlocksCovered) + push types back to ns
project to transform fields to be easier for next group
// cal coveredBlocks
group module&source to sum nsBlocksCovered -> coveredBlocks
project to transform fields to match your mongoose docs
My sample query with mongo shell syntax and its seem working , guess is you are using collection name "Coverage"
db.Coverage.aggregate([
{"$unwind":("$namespaces")}
,{"$unwind":("$namespaces.types")}
,{"$unwind":("$namespaces.types.functions")}
,{"$group": {
_id: {module:"$module", source:"$source", nsName: "$namespaces.name", typeName : "$namespaces.types.name"}
, typeBlocksCovered : { $sum : "$namespaces.types.functions.blocksCovered"}
, functions:{ "$push": "$namespaces.types.functions"}}}
,{"$project" :{module:"$_id.module", source:"$_id.source"
,namespaces:{
name:"$_id.nsName"
,types : { name: "$_id.typeName",typeBlocksCovered : "$typeBlocksCovered" ,functions: "$functions"}
}
,_id:0}}
,{"$group": {
_id: {module:"$module", source:"$source", nsName: "$namespaces.name"}
, nsBlocksCovered : { $sum : "$namespaces.types.typeBlocksCovered"}
, types:{ "$push": "$namespaces.types"}}}
,{"$project" :{module:"$_id.module", source:"$_id.source"
,namespaces:{
name:"$_id.nsName"
,nsBlocksCovered:"$nsBlocksCovered"
,types : "$types"
}
,_id:0}}
,{"$group": {
_id: {module:"$module", source:"$source"}
, coveredBlocks : { $sum : "$namespaces.nsBlocksCovered"}
, namespaces:{ "$push": "$namespaces"}}}
,{"$project" :{module:"$_id.module", source:"$_id.source", coveredBlocks : "$coveredBlocks", namespaces: "$namespaces",_id:0}}
])