lib/winston-config.js
function fromJson(winstonConf, callback) {
  if (_isEmpty(winstonConf)) {
    callback(new Error('Empty winston configuration'), winston);
    return;
  }

  configLogger(winstonConf);

  callback(null, winston);
}
function fromJson(winstonConf, callback) {
  if (_isEmpty(winstonConf)) {
    callback(new Error('Empty winston configuration'), winston);
    return;
  }

  configLogger(winstonConf);

  callback(null, winston);
}
initialize Winston logging mechanism from config (JSON) object each logger can be accessed via winston.loggers.get(NAME) in all modules running in this nodejs app