get virtual attribute for each nested object in an array of objects?

Question

get virtual attribute for each nested object in an array of objects?

So I know how to get a single virtual attribute, as stated in the Mongoose docs:

PersonSchema
 .virtual('name.full')
 .get(function () {
   return this.name.first + ' ' + this.name.last;
});

But what if my schema is:

var PersonSchema = new Schema({
    name: {
      first: String
    , last: String
    },

    arrayAttr: [{
      attr1: String,
      attr2: String
    }]
})

And I want to add a virtual attribute for each nested object in arrayAttr:

PersonSchema.virtual('arrayAttr.full').get(function(){
    return attr1+'.'+attr2;
});

Lemme know if I missed something here.

node.js
mongodb
express
mongoose

Answer 1

You need to define a separate schema for the elements of attrArray and add the virtual attribute to that schema.

var AttrSchema = new Schema({
    attr1: String,
    attr2: String
});
AttrSchema.virtual('full').get(function() {
    return this.attr1 + '.' + this.attr2;
});

var PersonSchema = new Schema({
    name: {
      first: String
    , last: String
    },
    arrayAttr: [AttrSchema]
});

Answer 2

First of all you should write

this.some_attr instead of some_attr

And you can't acces this.attr because there are in arrayAttr. So you can do for example:

this.arrayAttr[0].attr1 + "." + this.arrayAttr[0].attr2

This is not safe because arrayAttr can be empty