GCG: optimistic update throws type error when returning partial data

[drj17]

I'm trying to implement an optimistic update, updating the the phase of a projectInfluencer. In this schema, influencer is a non nullable field on projectInfluencer, but my mutation is not returning the influencer field because it isn't necessary.

mutation UpdateProjectInfluencerPhase($params: UpdateProjectInfluencerInput!) {
  updateProjectInfluencer(params: $params) {
    projectInfluencer {
      id
      projectPhase {
        id
      }
    }
  }
}

const optimistic: GraphCacheOptimisticUpdaters = {
  updateProjectInfluencer: (variables, _cache, _info) => ({
    __typename: 'UpdateProjectInfluencerPayload',
    projectInfluencer: {
      __typename: 'ProjectInfluencer',
      id: variables.params.id,
      projectPhase: {
        __typename: 'ProjectPhase',
        id: variables.params.projectPhaseId,
      },
    },
  }),
};

I think because the GraphCacheOptimisticUpdaters uses the regular mutation payload which in turn uses the types generates from the schema, the partial data I'm returning doesn't satisfy the type. The README says you only need to return the data that the mutation would be returning, so this seems like a bug with the generated types? Or maybe I'm just missing something 😄

urql version & exchanges:

{
    "@graphql-codegen/typescript-urql-graphcache": "^2.2.6",
    "@urql/exchange-graphcache": "^4.3.6",
    "urql": "^2.1.3",
}

Let me know if this should be raised in the graphql-codegen repo instead

[JoviDeCroock]

Isn't the top typename a Mutation? I don't think it's mandatory but that seems a bit off. What is the exception you are getting? Edit sorry I thought with throw you meant a js err

Yes the types could be off for that one, I think it will be quite hard to remedy this one

[drj17]

It seems to work without the top typename, that's also how it's shown in the documentation. I patched my package locally to recursively make the fields optional and nullable, which at least in my use case works well enough. I'm not versed enough in typescript to say if this will negatively affect type safety but at least my code compiles now 😄

[ghost]

I encountered the same issue. The problems seems to be that WithTypename marks an entity as Partial but not its child entities. As @drj17 mentioned a solution would be making WithTypename recursive:

export type WithTypename<T> = T extends { __typename?: any }
  ? Partial<{
      [K in keyof T]: T[K] extends Array<infer S>
        ? Array<WithTypename<S>>
        : T[K] extends object | undefined
        ? WithTypename<T[K]>
        : T[K];
    }> & { __typename: NonNullable<T["__typename"]> }
  : T;

Is there any reason you would not want the child entities to be partial?