Improve upsertNode function by allowing arithmetic modifications in the update part

[mfts]

Feature Request

What feature are you missing?

I would love a feature similar to what Graph.cool used to have with addTo function. Basically, when I run the function upsertNode and the node already exists, I don't want the update function to overwrite my node variables but have the option to add, subtract, multiply, or divide in case of floats and ints.

Why do I want this? Well if I already call upsertNode and my intention is to add two values, I don't want to know the value of existing node, I just care about adding my new value to it.

How could this feature look like in detail? Tradeoffs?

Consider this data model:

type User {
  id: ID! @unique
  name: String!
  numberOfLives: Int!
}

Suggestion

Add special parameters such as add, subtract, multiply, and divide as allowed update input

mutation {
  upsertUser(
    where: {
      id: "my-id"
    }
    create: {
      name: "some name"
      numberOfLives: 2
    }
    update: {
       add: { 
          numberOfLives: 2
       }
    }
  )
}

[schickling]

This should be covered by #1349 (Atomic operations). @sorenbs can you confirm this will also work for upsert mutations?

[sorenbs]

That's correct. The update part of upsert mutations have the same capabilities as normal update mutations, so when this feature lands it will also work for upserts.