winston + morgan logging middleware

logger.js

import config from '../config';
import winston from 'winston';

const logger = new (winston.Logger)({
  level: config.log.level,
  transports: [
    new winston.transports.Console({
      colorize: true,
      timestamp: true,
    })
  ]
});

export const getStream = (level) => ({
  write: (message) => logger[level](message.trim())
});

export default logger;

middleware.js

// HTTP request logging middleware
// This one handles successful responses (status < 400)
app.use(morgan('tiny', {
  stream: getStream('info'),
  skip: function (req, res) {
    return res.statusCode >= 400
  },
}));

// This one handles error responses (status >= 400)
app.use(morgan('tiny', {
  stream: getStream('error'),
  skip: function (req, res) {
    return res.statusCode < 400
  },
}));