"msg" field is empty

[DanielHreben]

In some reason this code

const bunyan = require('bunyan')
const logger = bunyan.createLogger({name: 'myapp'})
logger.warn({msg: 'test'})

will output log entry with empty "msg" field:

{"name":"myapp","hostname":"Daniels-MacBook-Air.local","pid":32837,"level":40,"msg":"","time":"2017-07-03T21:41:43.325Z","v":0}

[ORESoftware]

msg might be a predefined field? check the README

[ORESoftware]

when you close a question @DanielHreben it's good etiquette to explain what the problem/answer was so that you could potentially help others lol.

[DanielHreben]

@ORESoftware Well, I will be happy to explain that, but I don't understand real reasons, from your answer I only realize that's not a bug, since msg is a predefined field.
"err" is also predefined field, but it works that way:

logger.error({err: new Error()}) // "err" field will be present, everything is ok