Example of GraphQl issues with respect to filtering. Duplicated filter on data__noxe reference field. Also potentially conflicting with different versions.

1. README.md

Given a schema with three entities cases,products,noxe where cases and products link to noxe via field data__noxe and where the type noxe is a union of two major versions Noxe_v1 and Noxe_v2.

If the noxe should be filtered (by parent AND other properties) then the code to filter might be duplicated if put into the resolvers naively. The code can be easily be factored out but the duplication in the arguments remains AND is complicated by the fact that different filters might be needed for different versions of Noxe.

Looking at the line 4: data__noxe(match:"some n2") { we can see an argument data__value which is supposed to define a filter on field data__value. When adding another filter only present in one of the versions data__noxe(data__value:"eq:some n2" data__sometext:"contains:some") {

It would be nicer if the potential input arguments could be directly applied to the fields to avoid duplication on the server side and opt-in on the client side. See https://gist.github.com/matthiasg/c05696fd525768c735b57bdeca67c29e#file-4-field-level-filtering-mix

2. cases-to-noxe.gql

{
  cases {
    id
    data__noxe(data__value:"eq:some n2") {
      __typename
      ... on Noxe_v1 {
        id
        data__value
        data__sometext
      }
      ... on Noxe_v2 {
        id
        data__value
        data__somenumber
      }
    }
  }
}

3. products-to-noxe.gql

{
  products {
    id
    data__noxe(data__value:"eq:some n2") {
      __typename
      ... on Noxe_v1 {
        id
        data__value
        data__sometext
      }
      ... on Noxe_v2 {
        id
        data__value
        data__somenumber
      }
    }
  }
}

4. field level filtering (mix)

  products {
    id
    data__noxe() {
      __typename
      ... on Noxe_v1 {
        id
        data__value(eq:"some n2")
        data__sometext(contains:"some")
      }
      ... on Noxe_v2 {
        id
        data__value(eq:"some n2")
        data__somenumber(gt:2)
      }
    }
  }
}