Field 'message' from logged object ignored by Winston

[YuriGor]

Please tell us about your environment:

• winston version?
  • winston@2
  • winston@3.1.0
• node -v outputs: v10.7.0
• Operating System? Linux
• Language? ES5

What is the problem?

looks like Winston ignores field with name message

const winston = require('winston');

const logger = winston.createLogger({
  level: process.env.NODE_ENV === 'production' ? 'info' : 'debug',
  format: winston.format.simple(),
  transports: [new winston.transports.Console()],
});

const email = {
  subject: 'Hello, World!',
  message: 'Hello mr.World, sorry, but you will not see this message in the console.',
};

console.log('console.log:', email);//works as expected
logger.debug('logger.debug: ', email);//no 'message'
console.log('console.log again:', email);//still works as expected

Output:

console.log: { subject: 'Hello, World!',
  message:
   'Hello mr.World, sorry, but you will not see this message in the console.' }
debug: logger.debug:  {"subject":"Hello, World!"}
console.log again: { subject: 'Hello, World!',
  message:
   'Hello mr.World, sorry, but you will not see this message in the console.' }

What do you expect to happen instead?

I expect all the object will be displayed in the log without sudden exceptions

[GeekyDeaks]

this is related to #1510 - if the first argument is an object, it gets Object.assign()d with the logging object which already has level and message elements, so either of those will get overwritten

[indexzero]

Thank you for reporting this issue. The functionality is by design, but we updated examples & documentation in #1554 to make this less of a "gotcha". In this particular case if you use splat() you can get the behavior that you want:

const winston = require('winston');

const logger = winston.createLogger({
  level: process.env.NODE_ENV === 'production' ? 'info' : 'debug',
  format: winston.format.combine(
    winston.format.splat(),
    winston.format.simple()
  ),
  transports: [new winston.transports.Console()],
});

const email = {
  subject: 'Hello, World!',
  message: 'Hello mr.World, sorry, but you will not see this message in the console.',
};

logger.debug('logger.debug: %j', email);

This is very similar to the examples/splat-message.js that we added.