feat(createError): inherit fields from cause as fallback

[jerelmiller]

Resolves #691

Updates the logic for detecting the statusCode from an error by checking if it can be found on error.cause. This helps better detect a status code from an error created by a library that creates their own wrapped errors (such as Apollo Client's ApolloError class).

See apollographql/apollo-client#11634 for more context on this change. We've opened apollographql/apollo-client#11902 on our end to make this integration possible.

[jerelmiller]

Since cause can have all sorts of shapes, I find it best to do some type checking here before we try and parse from it. This is a bit verbose though compared to the first two conditional checks, so if you prefer more terseness, let me know and I'd be happy to pull this out to an external helper function.

[pi0]

Inline check is fine only cause can be null too (also saw it in apollographql/apollo-client#11902). typeof null === "object" and well next line fails so we can simplify it to truehy checking like input.cause?.statusCode.

[jerelmiller]

Should I also try and detect status from error.cause.status since this is also checked on the top-level properties, or should I just check statusCode here?

[pi0]

Thanks for PR dear @jerelmiller i will push some refactors to generalize it.

(also note, current main branch is targeting upcoming h3 v2, if more ecosystem backward compatibility adoption is needed, we might want to backport it to v1 as well)

[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 2 lines in your changes missing coverage. Please review.

Project coverage is 85.82%. Comparing base (a58d7c9) to head (0c75e01).
Report is 120 commits behind head on main.

Files	Patch %	Lines
src/error.ts	92.30%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #795      +/-   ##
==========================================
+ Coverage   77.83%   85.82%   +7.98%     
==========================================
  Files          47       44       -3     
  Lines        4286     4958     +672     
  Branches      611      673      +62     
==========================================
+ Hits         3336     4255     +919     
+ Misses        933      701     -232     
+ Partials       17        2      -15     

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[pi0]

Thanks again for PR and sorry for late review. I have pushed few refactors, simplifying implementation and also we use cause to inherit statusCode, statusMessage and fatal/unhandled fields (all which could be masked with wrapper)

[jerelmiller]

Wonderful. Thanks so much for the review and getting this in there!