bunyan-console-log.js

const stream = {
  level: 'warn',
  type: 'raw',
  stream: { write: (obj) => {
    console.log(
      [
        bunyan.nameFromLevel[obj.level],
        obj.msg,
        obj.err ? bunyan.stdSerializers.err(obj.err).stack : false
      ]
        .filter(item => !!item)
        .join(': ')
    );
  }}
};