Is winston logging framework is truly Async

I have no experience with Winston, other than I'm aware of it and its purpose. After a quick review of the source on github, I'd say that no, winston is not truly async in all aspects.

• It does emit, but EventEmitter is not async.
• Methods have an async-style signature (w/callback), but are not always async.

The Console transport calls callback without a nextTick - it has an async-style signature, but it is still within the same tick, i.e.:

Console.prototype.log = function (level, msg, meta, callback) {
  if (this.silent) {
    return callback(null, true);
  }
  //...
  if (level === 'error' || level === 'debug') {
    process.stderr.write(output + '\n');
  } else {
    process.stdout.write(output + '\n');
  }

  //
  // Emit the `logged` event immediately because the event loop
  // will not exit until `process.stdout` has drained anyway.
  //
  self.emit('logged');
  callback(null, true);
};

Logger is similar to Console as mentioned in previous in that it issues callbacks immediately w/o a nextTick (or some other real async op). It does use the async module, but that is not asynchronous on all accounts either, i.e.:

  function cb(err) {
    if (callback) {
      if (err) return callback(err);
      callback(null, level, msg, meta);
    }
    callback = null;
    if (!err) {
      self.emit('logged', level, msg, meta);
    }
  }

  async.forEach(this._names, emit, cb);

I will give Winston that its File transport is actually async, but only because fs is.

Don't forget that console.log is async within Node anyways... at least in my experience (when doing time-precision logging down to ms and even hrtime, results are sometimes out of order).