Extending generated graphql type and resolver

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1

Hi, I am trying to keep separated the files that rw generates and my own custom types and resolvers.
My question is:
I want to add a field to a generated type,
In my case for example I am managing some subscription options for the user to join an online service, so I have

// api/src/graphql/subscriptionTypes.sdl.ts
type SubscriptionType {
    id: Int!
    status: String!
    date_created: DateTime
    date_updated: DateTime
    slug: String
    cycle_length: Int!
    cycle_period: String
    price: Float!
    subscription_types_translations: [SubscriptionTypeTranslation]!
    user_subscriptions: [UserSubscription]!
  }

 type Query {
    subscriptionTypes: [SubscriptionType!]! @requireAuth
    subscriptionType(id: Int!): SubscriptionType @requireAuth
  }

the subscription type translation is a related table where I hold language specific strings, the model is like this


model SubscriptionType {
  id                              Int                           @id @default(autoincrement())
  status                          String                        @default("draft") @db.VarChar(255)
  ...
  price                           Decimal                       @db.Decimal(4, 2)
  subscription_types_translations SubscriptionTypeTranslation[]
  user_subscriptions              UserSubscription[]
}

model SubscriptionTypeTranslation {
  id                    Int               @id @default(autoincrement())
  subscription_types_id Int?
  languages_id          String?           @db.VarChar(255)
  name                  String?           @db.VarChar(255)
  description           String?
  languages             Language?         @relation(fields: [languages_id], references: [code], onUpdate: NoAction, map: "subscription_types_translations_languages_id_foreign")
  subscription_types    SubscriptionType? @relation(fields: [subscription_types_id], references: [id], onUpdate: NoAction, map: "subscription_types_translations_subscripti__2a003d1d_foreign")
}

The service for subscriptionTypes has this:


//api/src/services/subscriptionTypes/subscriptionTypes.ts
export const SubscriptionType: SubscriptionTypeRelationResolvers = {
  subscription_types_translations: (_obj, { root }) => {
    return db.subscriptionType
      .findUnique({ where: { id: root?.id } })
      .subscription_types_translations()
  },
  user_subscriptions: (_obj, { root }) => {
    return db.subscriptionType
      .findUnique({ where: { id: root?.id } })
      .user_subscriptions()
  },
}

Now I would like to be able to add a way for the subscriptionTypes query to just loaded the translations for a given language,

I noticed that I can just add a .sdl.ts file with the same type name and just add fields and they will get merged. So if I add:


// api/src/graphql/subscriptionTypesExtras.sdl.ts
export const schema = gql`
  type SubscriptionType {
    subscription_types_translation: SubscriptionTypeTranslation
  }

this new field gets merged into the type.
But now how do I add a resolver for this field?
Normally I would edit the relation resolver

//api/src/services/subscriptionTypes/subscriptionTypes.ts
export const SubscriptionType: SubscriptionTypeRelationResolvers = {
  subscription_types_translations: (_obj, { root }) => {
    return db.subscriptionType
      .findUnique({ where: { id: root?.id } })
      .subscription_types_translations()
  },
subscription_types_translation: (_obj, { root }) => {
    ...add my code here
  },
  user_subscriptions: (_obj, { root }) => {
    return db.subscriptionType
      .findUnique({ where: { id: root?.id } })
      .user_subscriptions()
  },
}

but then this file would be overwritten if I needed to regenerate the sdl for any reason.

Is there a way to get around this problem?

Thanks so much in advance

2

RW generators don’t handle all edge cases. As an example from the RW CLI docs for yarn rw generate sdl <model>:

The sdl will inspect your schema.prisma and will do its best with relations. Schema to generators isn’t one-to-one yet (and might never be).

But you can add custom generators (including for services). You should be able to extend the existing template with your added method.

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