I am trying to add a field to an aggregation called friendshipStatus and it determines whether the user is a friend of the requester or not.
I have this whole query:
[
{
$match: (query) ? query : {}
},
{
$addFields: {
friendshipStatus: {
$cond: {
if: {
$in: [vierweruserName || '', "$friends"]
},
then: "friend",
else: {
$cond: {
if: {
$in: [vierweruserName || '', "$friendRequests"]
},
then: "requested",
else: "none"
}
}
}
}
}
},
{
$project: {
_id: 0,
firstName: 1,
lastName: 1,
userDescription: 1,
userName: 1,
imgURL: 1,
coverURL: 1,
friendshipStatus: 1 // Include the new field in the output
}
},
{
$limit: 50
}
]
And I want to modify this addField stage to check if the user name is in the requester's friendRequests array or not (that would happen if he sent the requester a friend request)
{
$addFields: {
friendshipStatus: {
$cond: {
if: {
$in: [vierweruserName || '', "$friends"]
},
then: "friend",
else: {
$cond: {
if: {
$in: [vierweruserName || '', "$friendRequests"]
},
then: "requested",
else: "none"
}
}
}
}
}
}
I am expecting the code should also add the friendshipStatus as 'requested' if the user is in the array of friendRequests in the viewerUserName document. I wonder if I can do a subquery in the addFields stage to get the viewerUserName document and then search it or if there is another way.
Sample document:
{
"_id": "65034fed2153ebff85f30554",
"userName": "minamelad232",
"firstName": "mina",
"lastName": "melad",
"password": "$2b$10$Sr/cWOWwtAC9AQpHHLjFfuD3TKLIFvjd89QwgIJdz6cMB.rvWFeJy",
"userDescription": "No description",
"friends": ["minamelad123"],
"friendRequests": ["markosami123"],
"imgURL": "http://res.cloudinary.com/dik65evmf/image/upload/v1694726404/widgetUpl...",
"coverURL": "http://res.cloudinary.com/dik65evmf/image/upload/v1694715952/widgetUpl...",
"influence": 0,
"feedOffset": 0,
"commentsOffset": 0,
"friendRequestsOffset": 0,
"__v": 42
}
Sample output:
{
"userName": "minamelad232",
"firstName": "mina",
"lastName": "melad",
"userDescription": "No description",
"imgURL": "http://res.cloudinary.com/dik65evmf/image/upload/v1694726404/widgetUpload/qbegll5tmhumijplqkek.jpg",
"coverURL": "http://res.cloudinary.com/dik65evmf/image/upload/v1694715952/widgetUpload/f61ztmyvln0c5p0ei1db.png",
"friendshipStatus": "none"
}
Given that these are the sample (minimal) documents:
[
{
"_id": ObjectId("5a934e000102030405000000"),
"userName": "Alex",
"friends": [],
"friendRequests": [
//"may"
]
},
{
"_id": ObjectId("5a934e000102030405000001"),
"userName": "May",
"friends": [],
"friendRequests": [
"Alex"
]
}
]
As mentioned you need to search the viewer's friendRequests, this requires to self join the collection with userName: vierwerUsename
$lookup - Search the document in the same collection with userName: vierwerUsename and return the document in the array as viewer.
$addField - Would recommend using $switch operator for handling multiple conditions instead of nested $cond. For the third condition, you should match the condition with the userName in the document does existed in the friendRequest of the viewer.
{
$lookup: {
from: "collection", // replace with your collection name
pipeline: [
{
$match: {
$expr: {
$eq: [
vieweruserName || '',
"$userName"
]
}
}
}
],
as: "viewer"
}
},
{
$addFields: {
friendshipStatus: {
$switch: {
branches: [
{
case: {
$in: [
vieweruserName || '',
"$friends"
]
},
then: "friend"
},
{
case: {
$in: [
vieweruserName || '',
"$friendRequests"
]
},
then: "requested"
},
{
case: {
$in: [
"$userName",
{
$getField: {
field: "friendRequests",
input: {
$arrayElemAt: [
"$viewer",
0
]
}
}
}
]
},
then: "requested"
}
],
default: "none"
}
}
}
}