Winston not displaying error details

by

I think what you’re missing is format.errors({ stack: true }) in winston.createLogger.

const logger = winston.createLogger({
  level: 'debug',
  format: format.combine(
    format.errors({ stack: true }),
    print,
  ),
  transports: [new transports.Console()],
});

See this GitHub thread for more information.

The reason this is happening is because the interesting Error object properties, like .stack, are non-enumerable. Some functions check if the their parameters are Error instances, like console.error, and other functions ignore all non-enumerable properties, like winston.<log-level> and JSON.stringify.

> console.error(new Error('foo'))
Error: foo
    at repl:1:15
    at Script.runInThisContext (vm.js:124:20)
    ...(abbr)

> JSON.stringify(new Error('foo'))
'{}'

All that said, it’s horrible usability to have an error logger essentially ignore errors… I just lost too much time to this.

Leave a Comment