It looks like 3.0 is logging {} for Error objects

Hi All I am having some hassle with winston 3.0 logging empty error objects when it is using a json format.

module.exports = winston.createLogger({
  format: format.combine(
    format.label({ label: 'my label'}),
    format.timestamp(),
    format.prettyPrint()
  ),
  transports: [
    new (winston.transports.Console)({
      level: error
    })
  ]
}); 

logs the expected

 {error: [stack trace here] }

while

module.exports = winston.createLogger({
  format: format.combine(
    format.label({ label: 'my label'}),
    format.timestamp(),
    format.json()
  ),
  transports: [
    new (winston.transports.Console)({
      level: error
    })
  ]
}); 

logs the erroneous

{error: {} } 

when it is passed

logger.log({
  error: new Error('my error message')
 });

Manually creating a format with

winston.format.printf

also returned the erroneous result.

Does anybody know of a workaround for this?

[LukasBombach]

More concise version:

function format() {
  const replaceError = ({ label, level, message, stack }) => ({ label, level, message, stack });
  const replacer = (key, value) => value instanceof Error ? replaceError(value) : value;
  return combine(label({ label: 'ssr server log' }), format.json({ replacer }));
}

const logger = createLogger({
  format: format(),
});

But this is what I actually do to have pretty logs locally and JSON errors in production:

function prodFormat() {
  const replaceError = ({ label, level, message, stack }) => ({ label, level, message, stack });
  const replacer = (key, value) => value instanceof Error ? replaceError(value) : value;
  return combine(label({ label: 'ssr server log' }), format.json({ replacer }));
}

function devFormat() {
  const formatMessage = info => `${info.level} ${info.message}`;
  const formatError = info => `${info.level} ${info.message}\n\n${info.stack}\n`;
  const format = info => info instanceof Error ? formatError(info) : formatMessage(info);
  return combine(colorize(), printf(format))
}

const logger = createLogger({
  level: process.env.LOG_LEVEL || 'info',
  exitOnError: false,
  transports: [new transports.Console()],
  format: isProd ? prodFormat() : devFormat(),
});

which gives me this in production

and this in development

[dhensen]

I’m running into this as well. Shouldn’t winston handle this out of the box? @indexzero what do you think about this?