Node-bunyan: What is the 2nd argument in `log.child()`?

[ronkorving]

The readme shows an example:

log.child({req_id: <unique request id>}, true)

But nowhere in the readme (as far as I can tell) are the arguments for log.child() explained beyond:

to create a new logger with additional bound fields that will be included in its log records

[ronkorving]

update: I've found the answer, but I will leave this issue open, because I think it deserves documentation.

[ORESoftware]

Yeah, maybe try the TypeScript typings if you really get stuck.

What is the second argument? If you figured it out, maybe submit a PR for the docs?

[ronkorving]

I'm sorry to say that I forgot 😭
It's been a while.

[dnunes]

The second parameter is "simple" flag for child log creation.

In the code: https://github.com/trentm/node-bunyan/blob/master/lib/bunyan.js#L346

@param _childSimple (Boolean) An assertion that the given `_childOptions`
(a) only add fields (no config) and (b) no serialization handling is
required for them. IOW, this is a fast path for frequent child
creation.

The code path that uses this flag is in https://github.com/trentm/node-bunyan/blob/master/lib/bunyan.js#L394, for those who are interested in digging a little bit further.

There is a last reference for this flag effects on https://github.com/trentm/node-bunyan/blob/master/lib/bunyan.js#L739, but it looks like that part of the code is commented out for some reason. A git blame would probably lead to the commit and reason behind that, but I'm not motivated enought about the subject.

[shsh1177]

나닌
2018년 6월 4일 (월) 09:14, diego nunes [e-mail]님이 작성:

The second parameter is "simple" flag for child log creation.

In the code:
https://github.com/trentm/node-bunyan/blob/master/lib/bunyan.js#L346

@param _childSimple (Boolean) An assertion that the given _childOptions
(a) only add fields (no config) and (b) no serialization handling is
required for them. IOW, this is a fast path for frequent child
creation.

The code path that uses this flag is in
https://github.com/trentm/node-bunyan/blob/master/lib/bunyan.js#L394, for
those who are interested in digging a little bit further.

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