Virtuals On Populated Document Require Parent .toObject modification to be set

[Benjamin Clos]

Hey guys,

After searching for a bit on Google I found no relevant answers to why populated document virtuals are not set when the parent document they are populated on has its Document#toObject method invoked.

Example Schema definitions:

  mongoose = compound.mandyGet('mongoose')

  Image = new mongoose.Schema

    stem: 

      type: String

      unique: true

      searchable: true

    tags: []

    ext: String

    types: []

    _job:

      type: mongoose.Schema.Types.ObjectId

      ref: 'Scope'

  Image.virtual('urls').get ->

    urls = {}

    urls[type]= "#{@stem}-#{type}.#{@ext}" for type in @types

    urls
  
  Image.set 'toObject', virtuals: true
 
   Product = new mongoose.Schema
     images: [{

      type: mongoose.Schema.Types.ObjectId

      ref: 'Image'

    }]

  compound.models.Image = compound.mandyGet('mongoose').model 'Image', Image
  compound.models.Product = compound.mandyGet('mongoose').model 'Product', Product

Notice how Image has been flagged as virtuals: true

However, when you run:

c.Model.Product
  .findById('fakeid')
  .populate('images')
  .exec (err, product)=>
    c.res.json product # here it is turned into an object to send to the client but will not have image.urls defined on the client-side

The virtuals from the Image Schema will not be returned in this scenario.  To fix this problem you would have to set the Product schema virtuals:true.

I am not sure if this is easily fixable, as recursively checking populated documents for virtuals looks like it will cause issues elsewhere, but I thought it bore documentation.