Interface inheritance - Githubissues

Dear Nicolas,

Inheritance is really missing from GraphQL, so this library is a great contribution to the ecosystem!

I'm currently running into a use case where we want to inherit with an interface. This currently works by doing something like this :

type NodeParent {
    id: ID!
}

interface Node {
    id: ID!
}

type Person inherits NodeParent implements Node {
    firstname: String
    lastname: String
}

This is a bit verbose, but we also end up with a type that we will never use (NodeParent). This "abstract class" will be visible to the user through GraphQL introspection.

I have an alternative in mind that allows developers to still hand pick interface implementation, but allows them to inherit when they want to. It would allow inheriting from interfaces.

What I was thinking of was code that transpiles this :

interface Node {
    id: ID!
}

type Person inherits Node implements Node {
    firstname: String
    lastname: String
}

type Student inherits Person {
    nickname: String
}

type Query {
  students: [Student]
}

into this :

interface Node {
    id: ID!
}

// Person has inherited the "id" field and implements the interface
type Person implements Node {
    id: ID!
    firstname: String
    lastname: String
}

// Student has inherited the fields from Person, but the 
// developer chose not to implement the interface
type Student {
    id: ID!
    firstname: String
    lastname: String
    nickname: String
}
type Query {
    students: [Student]
}

I've built this locally with minimal code changes and was wondering if you would accept a PR that allowed this use case.

Kind regards, Mike

nicolasdao / graphql-s2s

Interface inheritance #18