Can not log variables that are `null` or `undefined`

Hello! I’m having an issue with logging variables if I expect them to sometimes be null or undefined.

I am using a custom formatter, but disabling this does not fix the problem.

Error when console.log()-ing the error:

TypeError: Cannot read property 'message' of undefined
    at DerivedLogger.(anonymous function) [as debug] (<...>\node_modules\winston\lib\winston\create-logger.js:43:26)

And from my logger logging its own error,:

15:52:25 error: Cannot read property 'message' of undefined

Steps to reproduce

1. Call a winston logger with an undefined variable or object, e.g. logger.debug(null); or let myVar = undefined; logger.info(myVar);.

Expected behaviour

1. Winston logs the error according to all the formats applied to it.
2. Execution continues.

Actual behaviour

1. Winston logs a Cannot read property 'message' of null/undefined error.
2. Execution halts.

System info

• Windows 10
• NodeJS v. 8.9.1
• npm v. 5.6.0
• winston v. 3.0.0-rc1

[DABH]

Sorry, does this also happen with the latest rc (3.0.0-rc5)? If so, any chance you can show us how your logger and transports are setup/defined?

[dagerikhl]

Wow, I’m really nailing it with the searches! Thanks for clearing that up, and thanks for the help. If I think of some way to handle it, I’ll be sure to comment.