populated virtuals are always an array

virtual population is using find method to do its population stuff, so result is always an array however relation can be one-to-one in many cases and this causes some redundant calculation

• find searches over all collection, while findOne stops on first result
• code have additional complexity in x.y[0].value this [0] is redundant it would be nice to have ability to specify a relation type in any acceptable way

XSchema.virtual("y", {
    ref: "Y",
    localField: "_id",
    foreignField: "x",
    singular: true // <-- here
});

[vkarpov15]

@AleksMeshkov added a quick note about it in the populate docs 👍

[vkarpov15]

Thanks for taking the time to look at this new feature and point out issues 👍