Upsert mutation or createOrUpdate

Hello. I read the graphql doc and find there isn't exist mutation of upsert(or createOrUpdate) which is very useful in batch update, it has been implemented by Dgraph.
I only find connectOrCreate which can create or connect the node, but don't offer hook to UPDATE the property's value of match(connect) node.

Say we have a schema

type Product {
  id: ID @id
  name: String
  hsCode: String
  price: Currenty @relationship(type: "HAS_PRICE", direction: OUT)
type Currenty {
  id: ID @id
  currencyCode: CurrencyCode @default(value: USD)
  amount: Float!

enum CurrencyCode {
  "US Dollar"
  "EURO Currency "
  "Japan Yuan"
  "Hongkong Dollar"
  "China Yuan"
  CNY #ISO 4217

I want to update the name of Product and amount of price within same mutation. Sometime we will offer price when create product, but something not.
So when I want to update price of product, there maybe has not price(type: Currency).
What I expected is when the price is not exsisted(determined by id), it will created a new one, if the price's id exist, it will update the node with the given data within some method such as onUpdate or onCreateOrUpdate...

mutation xx{
            name: "Foobar"
				connectOrCreate:{ // I want another upsert operation here
					onCreate // It should have onConnect hook too. So we can update the node here, such as onConnect { node: { name: "Product A" } }, we will match the node and UPDATED at the same time here.
                                        // if will have onCreateOrUpdate hook here, it will be great, I will update or create from given data without considering which type(create or connect) of mutation it take.

So I was stuck now, I can't update the price if the id exist. I have to write another Mutation to do this task. So I have two Mutation for nested update, also I have to judge if the price's id(type Currency) is exisit before I decide which Mutation to apply.