Document match and other populate() options as options to Schema#virtual() and VirtualType constructor

[dar097]

Do you want to request a feature or report a bug?
Feature

Code snippet for use in explanations
Model.populate({ path: 'items', match: { status: 'purchased' }, as: 'purchased_items' }).populate({ path: 'items', as: 'all_items' })

What is the current behavior?
Using the above code snippet, the 'as' is ignored, and the last populate overrides the previous one, resulting in all items being returned under the name 'items'.

What is the expected behavior?
By providing the 'as' property, each populate is returned under its defined 'as' value, items with the status of 'purchased' under the property 'purchased_items' and all items under the property 'all_items'. This ideally would also work with virtual populate, allowing also count operations to be separable.

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
Node.js: 10.16.0
Mongoose: 5.8.4
Mongodb: 3.4.1

[vkarpov15]

Why not just have purchased_items and all_items as populate virtuals?

schema.virtual('purchased_items', {
  ref: 'Item',
  localField: 'items',
  foreignField: '_id',
  justOne: false,
  match: { status: 'purchased' }
});

schema.virtual('all_items', {
  ref: 'Item',
  localField: 'items',
  foreignField: '_id',
  justOne: false
});

[dar097]

Why not just have purchased_items and all_items as populate virtuals?

schema.virtual('purchased_items', {
  ref: 'Item',
  localField: 'items',
  foreignField: '_id',
  justOne: false,
  match: { status: 'purchased' }
});

schema.virtual('all_items', {
  ref: 'Item',
  localField: 'items',
  foreignField: '_id',
  justOne: false
});

I was under the impression that match was not usable in virtual population, I'll try it out when I can.. If it is possible, is there any documentation of everything else that is possible here?

[vkarpov15]

You can use match with virtual populate. In general, conventional populate and virtual populate support the same options. The API docs have a list of all options for populate().

We need to add these options to the VirtualType constructor's API docs.