MongoDB conditional aggregation with unwind - mongodb

Question

I have db collection like:
{
"_id" : "af5c00e4-d3a8-419d-8793-c0cf328802ec",
"collaborators" : [
{
"_id" : "9bd2eee8-bf6c-4c6f-bab7-d2d175aed807",
"origin" : [
{
"originId" : "123"
}
],
"firstName" : "Parveen",
"lastName" : "Vendor",
"email" : "pk#gmail.com"
},
{
"_id" : "234324-bf6c-4c6f-bab7-d2d175aed807",
"origin" : [
{
"originId" : "1234"
}
],
"firstName" : "Parveen123",
"lastName" : "34",
"email" : "abc#gmail.com"
}
],
"orders" : [
{
"totalAmount" : 10,
"collaborators" : [
{
"origin" : [
{
"originId" : "123",
}
],
"type" : "Supplier"
},
{
"origin" : [
{
"originId" : "1233",
}
],
"type" : "Supplier"
}
]
}
]
}
Want to replace data in orders (array) collaborators(array) with
**collaborators(array) ** data if matches originId of both
Expected output
{
"_id" : "af5c00e4-d3a8-419d-8793-c0cf328802ec",
"collaborators" : [
{
"_id" : "9bd2eee8-bf6c-4c6f-bab7-d2d175aed807",
"origin" : [
{
"originId" : "123"
}
],
"firstName" : "Parveen",
"lastName" : "Vendor",
"email" : "pk#gmail.com"
},
{
"_id" : "234324-bf6c-4c6f-bab7-d2d175aed807",
"origin" : [
{
"originId" : "1234"
}
],
"firstName" : "Parveen123",
"lastName" : "34",
"email" : "abc#gmail.com"
}
],
"orders" : [
{
"totalAmount" : 10,
"collaborators" : [
{
"_id" : "9bd2eee8-bf6c-4c6f-bab7-d2d175aed807",
"origin" : [
{
"originId" : "123"
}
],
"firstName" : "Parveen",
"lastName" : "Vendor",
"email" : "pk#gmail.com"
},
{
"origin" : [
{
"originId" : "1233",
}
],
"type" : "Supplier"
}
]
}
]
}
One collection record can have multiple collaborators , same as order can have multiple collaborators.
Need to replace only where originId matches

Answer 1

One option is:
Use $map, $mergeObjects and $filter to add a new key to each item of orders.collaborators with the matching item from collaborators if exists.
choose the new key if it contains data or the original key, if not.
db.collection.aggregate([
{$set: {
ordersCollaborators: {
$map: {
input: {$first: "$orders.collaborators"},
in: {$mergeObjects: [
{original: "$$this"},
{new: {
$filter: {
input: "$collaborators",
as: "i",
cond: {
$eq: [
{$first: "$$i.origin.originId"},
{$first: "$$this.origin.originId"}
]
}
}
}
}
]
}
}
}
}
},
{$set: {
orders: [
{totalAmount: {$first: "$orders.totalAmount"},
collaborators: {
$map: {
input: "$ordersCollaborators",
in: {
$cond: [
{$eq: [{$size: "$$this.new"}, 0]},
"$$this.original",
"$$this.new"
]
}
}
}
}
],
ordersCollaborators: "$$REMOVE"
}
}
])
See how it works on the playground example