Correctly type the return values when creating schemas, credential definitions and dids

[auer-martin]

The return types are not correctly typed, and therefore need to be casted. See the snippet below.

          (await agent.modules.anoncreds.registerCredentialDefinition<IndyVdrRegisterCredentialDefinitionOptions>(
            {
              credentialDefinition,
              options: {
                endorserMode: 'external',
                endorserDid,
              },
            }
          )) as IndyVdrRegisterCredentialDefinitionReturn

[hs2361]

Hi @2mau, I'm new to AFJ and I'd like to start contributing by working on this issue. From what I found, https://github.com/hyperledger/aries-framework-javascript/blob/bd4932d34f7314a6d49097b6460c7570e1ebc7a8/packages/indy-vdr/src/anoncreds/IndyVdrAnonCredsRegistry.ts#L307-L310

the function signature does seem to have the correct types. Could you please elaborate as to what changes this issue is supposed to encompass, since I'm new to the code base?

[auer-martin]

Hi, @hs2361. I'll try to explain the problem to you in more detail, but I'm not 100% sure if this is the right way. Maybe @TimoGlastra can also take a look at this problem, and give his opinion.

For anoncreds, there is an API called AnoncredsApi which is the public-facing part. In this file, you can find the registerCredentialDefinition and registerSchema functions. Currently, registerCredentialDefinition allows Providing a generic Type T to type its input values. The issue is that by typing the Input values as IndyVdrRegisterCredentialDefinitionOptions the return value should become IndyVdrRegisterCredentialDefinitionReturn, but instead the more Generic RegisterCredentialDefinitionReturn type is used, that is why the cast is required. In the IndyVdrAnonCredsRegistry (the snippet you posted), the typing is still correct, but it is not correctly propagated towards the public-facing part of the API.

I think we need to find solutions here in multiple places.

• First, there are multiple networks/registries that can be used with Anoncreds. In AfJ currently the IndyVdrAnonCredsRegistry and CheqdAnonCredsRegistry are supported. So when calling RegisterCredentialDefinition, there is a function findRegistryForIdentifiers which is used to find the correct registry. But that function already returns the more Generic AnoncredsRegistry instead of indy-vdr/cheqd AnoncredsRegistry.
• Second, So we need to create a mechanism that based on the input types of the AnoncredsApi registerCredentialDefinition/Schema methods adds proper typing to the findRegistryForIdentifiers.
• Third, we need to somehow type the return value of the AnoncredsApi RegisterSchema/CredentialDefinition method as the result of calling the registry-specific RegisterSchema/CredentialDefinition.