[BUG] errorKey is not set when pinoHttp is a tuple

[AndrewBird81]

• I've read the docs of nestjs-pino
• I've read the docs of pino and pino-http
• I couldn't find the same open issue of nestjs-pino
• This bug is related only to current library or I've tested the same behaviour with the built-in logger and this is not a bug of NestJS.

What is the current behavior?
PinoLogger's errorKey is not properly initialized when pinoHttp is supplied as a tuple.

Inside the PinoLogger constructor, the errorKey is initialized (or defaulted) as such:

if (
  typeof pinoHttp === 'object' &&
  'customAttributeKeys' in pinoHttp &&
  typeof pinoHttp.customAttributeKeys !== 'undefined'
) {
  this.errorKey = pinoHttp.customAttributeKeys.err ?? 'err';
}

However, the Options for pinoHttp could also be supplied as a tuple:

pinoHttp?: Options | DestinationStream | [Options, DestinationStream];

And when pinoHttp is supplied as the tuple [Options, DestinationStream], the above logic fails, resulting in this.errorKey being incorrectly defaulted to err, despite having a valid customAttributeKeys.err defined in the Options.

What is the expected behavior?
Users should be able to use any valid signature of pinoHttp without losing the ability to specify their errorKey.

Please provide minimal example repo, not code snippet. Without example repo this issue will be closed.
Sorry, I already spent my Saturday tracking down this bug. You can close this issue if you want, but a cursory glance will prove its validity.

Please mention other relevant information such as Node.js version and Operating System.
N/A

[iamolegga]

@AndrewBird81 thanks for opening this issue, would you like to open a PR for this issue?