Add support for throwing errors with custom error code

[palamccc]

Motivation:

In the rsocket-js implementation (v0 branch), all stream errors are serialized and transmitted to other end with fixed error code. Due to this bug, there is no way to send custom error codes over stream (Bug report #218)

Custom error codes are supported in the rsocket protocol and implemented in rsocket-java this using RSocketErrorException . When the application throws RSocketErrorExecption, the error code of the exception is sent over the stream. But this feature is not implemented in rsocket-js.

Modifications:

• This PR adds custom Javascript Error class RSocketError in RSocketError.js.
• When the application throws error of type RSocketError, the errorCode of the error object is sent over the stream.

Result:

This will allow application to send custom error codes to other party.

[viglucci]

Hey @palamccc thanks for the contribution!

Would you be able to add tests for your changes? Looks like RSocketServer-test.js might have good examples to build off of.

https://github.com/rsocket/rsocket-js/blob/master/packages/rsocket-core/src/__tests__/RSocketServer-test.js#L144-L151

Additionally the DCO check will ideally need to be resolved before this can be merged.

[viglucci]

This might be best as its own file RSocketError.js.

[palamccc]

Done 👍🏽

[palamccc]

Would you be able to add tests for your changes? Looks like RSocketServer-test.js might have good examples to build off of.

@viglucci I've added tests now.

[viglucci]

LGTM. Thanks! I'll LYK when a new version is published.

[palamccc]

I've contributed types to DefinitelyTyped DefinitelyTyped/DefinitelyTyped#68788
Waiting for 0.0.28 release :-).

[viglucci]

@palamccc I've published a new version which should include this change. If you would be so kind, please validate this change with rsocket-core@0.0.29-alpha.0.