Mongoosejs virtual populate

Question

I have a circle model in my project:

var circleSchema = new Schema({
//circleId: {type: String, unique: true, required: true},
patientID: {type: Schema.Types.ObjectId, ref: "patient"},
circleName: String,
caregivers: [{type: Schema.Types.ObjectId}],
accessLevel: Schema.Types.Mixed
});

circleSchema.virtual('caregiver_details',{
    ref: 'caregiver',
    localField: 'caregivers',
    foreignField: 'userId'
});

caregiver schema:

var cargiverSchema = new Schema({
    userId: {type: Schema.ObjectId, unique: true},  //objectId of user document
    detailId: {type: Schema.ObjectId, ref: "contactDetails"},
    facialId: {type: Schema.ObjectId, ref: "facialLibrary"}, //single image will be enough when using AWS rekognition
    circleId: [{type: Schema.Types.ObjectId, ref: "circle"}],           //multiple circles can be present array of object id
});

Sample Object:

{ 
    "_id" : ObjectId("58cf4832a96e0e3d9cec6918"), 
    "patientID" : ObjectId("58fea8ce91f54540c4afa3b4"), 
    "circleName" : "circle1", 
    "caregivers" : [
        ObjectId("58fea81791f54540c4afa3b3"), 
        ObjectId("58fea7ca91f54540c4afa3b2")
    ], 
    "accessLevel" : {
        "location\"" : true, 
        "notes" : false, 
        "vitals" : true
    }
}

I have tried virtual populate for mongoosejs but I am unable to get it to work. This seems to be the exact same problem: https://github.com/Automattic/mongoose/issues/4585

circle.find({"patientID": req.user._id}).populate('caregivers').exec(function(err, items){
        if(err){console.log(err); return next(err) }
        res.json(200,items);
    });

I am only getting the object id's in the result. It is not getting populated.

One note: you must add ref property here: userId: {type: Schema.ObjectId, unique: true}, — Sergaros, May 10 '17 at 08:36
I mean you forgot about ref property: userId: {type: Schema.ObjectId, unique: true, ref: 'user'} — Sergaros, May 10 '17 at 10:22
@Sergaros that did not work either. not sure what is happening. :( — Himanshu Jain, May 10 '17 at 10:26
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/143865/discussion-between-himanshu-jain-and-sergaros). — Himanshu Jain, May 10 '17 at 10:28
Did you try example from docs: http://mongoosejs.com/docs/populate.html — Sergaros, May 10 '17 at 10:28
I have made a big mistake. Referencing refers to the _id. Whereas the records I have in circle schema have userId object ids. Is there a way to reference that? — Himanshu Jain, May 10 '17 at 10:44
The virtual populate seems to be the solution. Although, I can still not get it to work. — Himanshu Jain, May 10 '17 at 10:54
This seems to be the exact issue. but does not work for me: https://github.com/Automattic/mongoose/issues/4585 — Himanshu Jain, May 10 '17 at 11:01
I also have the same. this link: https://stackoverflow.com/questions/63483501/virtual-populate-with-mongoose — Hoàng Minh Phan, Aug 19 '20 at 09:53

Himanshu Jain · Accepted Answer · 2017-05-11T03:03:44.017

73

Figured out what the problem was. By default, the virtual fields are not included in the output. After adding this in circle schema:

circleSchema.virtual('caregiver_details',{
    ref: 'caregiver',
    localField: 'caregivers',
    foreignField: 'userId'
});

circleSchema.set('toObject', { virtuals: true });
circleSchema.set('toJSON', { virtuals: true });

It now works perfectly.

edited May 11 '17 at 03:03

answered May 10 '17 at 20:14

Himanshu Jain

1,709
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YEEEEES! Thank you! It took me days to finally figure this out. Virtual fields are not included as clearly [stated in the docs](https://mongoosejs.com/docs/guide.html#virtuals). Somehow I only remembered this about toJSON -- but I didn't see it for toObject even though it's on the same line. – Alex D Nov 16 '18 at 17:45

score 2 · Answer 2 · answered Dec 31 '19 at 12:15

2

If you use expressJs res.json method it's ehough to add only:

yourSchema.set('toJSON', { virtuals: true });

Or you can directly use toJSON/toObject:

doc.toObject({ virtuals: true })) // or doc.toJSON({ virtuals: true }))

answered Dec 31 '19 at 12:15

zemil

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Mongoosejs virtual populate

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