How to add local only fields for interface type Objects?

I’m working on a Chat Application which have several types of Messages. Our graphql schema is defined as below. (we call a chat as ‘counsel’ in this project)

interface Message {
  id: ID!
  author: User!
  counsel: Counsel!
  createdAt: DateTime!
}
type TextMessage implements Message {
  id: ID!
  author: User!
  counsel: Counsel!
  createdAt: DateTime!
  body: String!
}
type FileMessage implements Message {
  id: ID!
  author: User!
  counsel: Counsel!
  createdAt: DateTime!
  file: File!
}
type ShopMessage implements Message {
  id: ID!
  author: User!
  counsel: Counsel!
  createdAt: DateTime!
  shop: Shop!
}
type InvoiceMessage implements Message {
  id: ID!
  author: User!
  counsel: Counsel!
  createdAt: DateTime!
  order: Order!
}
# etc...

For the frontend react application, I wanted to add local only field status on Message interface to control UI of message sending status.

Expected Behavior

// src/utils/cache.ts
// use local only 'status' field on every type of Messages!
export const typeDefs = gql`
  enum MessageStatus {
    PENDING
    SENT
    FAILED
  }
  extend interface Message {
    status: MessageStatus!
  }
`;

When I run graphql codegenerator after writing code as above, it gave me Error log as below.

    Error: Type EndWarningMessage must only implement Interface types, it
 cannot implement Message.

    Type EnterMessage must only implement Interface types, it cannot impl
ement Message.

    Type FileMessage must only implement Interface types, it cannot imple
ment Message.

    Type InvoiceMessage must only implement Interface types, it cannot im
plement Message.

    Type LeaveMessage must only implement Interface types, it cannot impl
ement Message.

    Type RestartMessage must only implement Interface types, it cannot im
plement Message.

    Type ShopMessage must only implement Interface types, it cannot imple
ment Message.

    Type TextMessage must only implement Interface types, it cannot imple
ment Message.

What I had to do to work

After reading Error log and trying several times, I’ve succeed to let Application work, but I had to add status field for every implemented Message types as described below.

// src/utils/cache.ts
export const typeDefs = gql`
  enum MessageStatus {
    PENDING
    SENT
    FAILED
  }
  extend type TextMessage {
    status: MessageStatus!
  }
  extend type FileMessage {
    status: MessageStatus!
  }
  extend type ShopMessage {
    status: MessageStatus!
  }
  extend type InvoiceMessage {
    status: MessageStatus!
  }
`;

Question

Is there any cool way to extend my Message interface, which can add my status field to every type of Messages at once?

[benjamn]

@Hemistone I believe GCG is able to generate typed typePolicies via StrictTypedTypePolicies, though I haven’t tried it myself, so I’d be interested to hear how it goes!

[jpvajda]

I’m going to close this one out as this issue had a response to help the reported problem.