Circular reference with JSON format causes an unhandled exception

[kingjerod]

Please tell us about your environment:

• winston version?_
  • winston@2
  • [email protected]
• node -v outputs: v10.1.0
• Operating System: Linux (Official Docker image)
• Language: TypeScript 2.6.2

What is the problem?

Logging a variable with a circular reference causes an unhandled exception.

What do you expect to happen instead?

I would expect the exception would be caught and a warning message printed. Or the circular reference would be noted in the resulting JSON, like util.inspect does. Something like:
https://www.npmjs.com/package/circular-json

Other information

Here is the code:

const log = createLogger({
  format: format.json(),
  transports: [new transports.Console()]
});

const a = {name: "A"};
const b = {name: "B", a: a};
a["b"] = b;
log.info("B:", b);

Error Message:

/app/node_modules/logform/json.js:23
  info[MESSAGE] = JSON.stringify(info, opts.replacer || replacer, opts.space);
                       ^

TypeError: Converting circular structure to JSON
    at JSON.stringify (<anonymous>)
    at Format.module.exports.format [as transform] (/app/node_modules/logform/json.js:23:24)
    at Format.info [as transform] (/app/node_modules/logform/combine.js:20:24)
    at DerivedLogger._transform (/app/node_modules/winston/lib/winston/logger.js:220:27)
    at DerivedLogger.Transform._read (_stream_transform.js:190:10)
    at DerivedLogger.Transform._write (_stream_transform.js:178:12)
    at doWrite (_stream_writable.js:413:12)
    at writeOrBuffer (_stream_writable.js:397:5)
    at DerivedLogger.Writable.write (_stream_writable.js:295:11)
    at DerivedLogger.log (/app/node_modules/winston/lib/winston/logger.js:176:10)

[indexzero]

Duplicate of #1248. The reasoning behind this behavior is outlined here: #1248 (comment). TL;DR? Write your own format which handles circular JSON.

[indexzero]

FYI circular JSON is supported by default thanks to winstonjs/logform#35