[TypeScript] Missing type generation for a union that only resolves __typename

Describe the bug If you only query a union for the __typename, codegen doesn’t generate a type but still references it. See example:

To Reproduce Steps to reproduce the behavior:

1. Write a schema containing a union
2. Query for the union __typename only

Expected behavior A type with only the __typename should be generated. I.e. in this case the generated file should also contain:

export type UserUnion = {
  __typename: "OneUnion" | "TwoUnion";
}

[dotansimha]

Fixed in the recent refactor 😃

[dotansimha]

Thanks for reporting if @csoLs ! We are filtering __typename and ignoring it from the fields list. It requires a more complex solution.

At the moment we are looking for refactoring the typescript packages, and use the same approach as flow plugins (use Pick and build a single type only, instead of namespace with multiple interfaces), and we also implemented there a solution for __typename fields).