how to display content of a document into another document using mongoose virtual

Question

I'm trying to write a Eshop Application and I want to get total price of a product multiplied by the product count using virtuals

this is my "cart-item" schema

const cartItem = new Schema(
  {
    user: {
      type: mongoose.Schema.Types.ObjectId,
      ref: "user",
    },
    products: [productSchema],
  },
  { timestamps: true }
); 

//Product Schema
const productSchema = new Schema({
  productId: { //ref to Product Schema, [simple schema with name, price and properties ]
    type: mongoose.Schema.Types.ObjectId,
    ref: "product",
  },
  quantity: {
    type: Number,
    default: 1,
    required: true,
  },
});

productSchema.virtual("price").get(function () {
 const price = **// How to get price from "productId" and return as virtual**
  return "virtual";
});

how can i get the product price and get from the virtual ?

Answer 1

You can use just a this.price

productSchema.virtual("price").get(function () {
   return this.price * something; // You price calculations;
});

virtual works with current data instance, after it initialisation. Any asyncronouse oprations must be completed before virtual usage. This is just a sugar code, which works with ready to use data