TypeScript Resolvers plugin doesn't allow null to be returned from a promise

[timothyarmes]

Describe the bug
Given a query with an optional response:

type Query {
  subscription: SubscriptionDetails
}

I should be able to write a resolver that returns a promise that returns null:

const subscription: QueryResolvers["subscription"] = async (
  _root,
  _args,
) => {
  return await fetchResult(); // Might return null
}

However, I can't because the return type is defined like this:

Maybe<ResolverTypeWrapper<SubscriptionDetails>>

So I can return null immediately (thanks to the Maybe), but if I return a Promise then I have to return ResolverTypeWrapper<SubscriptionDetails>, which is defined as:

export type ResolverTypeWrapper<T> = Promise<T> | T;

Where the type T itself (SubscriptionDetails in the example) isn't null, so I can't return null.

Proposed Solution:

If the response is optional then the generated code should be something like:

Maybe<ResolverTypeWrapper<Maybe<SubscriptionDetails>>>

[dotansimha]

Hi @timothyarmes and thank you for the report!

Sorry but I'm not adding a lot here but just labeling it according to our new Contribution Guide and issue flow.

It seems like we are on stage 0.
Now in order to advance to stage 1 we'll need an easily running reproduction, do you think you can create that on code sandbox?

Thank you and sorry that this comment is not a complete solution (yet).

[jonparkdev]

@timothyarmes I've run into this too. Did you find out any more information about this issue?