Serialize non-error cause

[Andreyco]

Issues:

• The non-error cause property set via constructor is not retained.
• The non-error "cause" is not included in the stack

Why is that happening:

• Serializers have logic that only allows error like "cause", while runtime is very permissive (in fact, it's typed as { cause?: unknown }
• In addition the cause property set via the constructor is non-enumerable. The serializers were primarily using a for...in loop to find extra properties, which skips non-enumerable ones.

Why the change:

• while one should not, it's possible to throw 42
• but it perfectly ok to Promise.reject(42)
• it partially supported by the lib (via err.cause = 42, but not via Error('ooops', { cause: 42 }))

I really hope per commit "evolution" helps in review process.

[Andreyco]

I also consider presence of cause on SerializedError to be an issue.
Can solve that, however would break existing test suite and want to prevent mixing things.

[mcollina]

lgtm

[jsumners]

I don't think we should promote handling of not errors.

[mcollina]

Neither do I tbh. @Andreyco what does it currently happen?

[Andreyco]

hello everyone, thanks for finding time to respond...

I don't think we should promote handling of not errors.

Neither do I tbh. @Andreyco what does it currently happen?

Basically, Promises rejected with non error as reason is the motivation for this PR. It's way too common among 3rd party packages.

If you are 100% against and won't accept non error-like variant, let me reiterate on this PR, as there are some internal changes preventing me from writing custom wrapper around for error serializer (afaik cause not being preserved, it's some time since I wrote this)

Waiting for your response before acting. TY!