Winston logging with formatting

winston-logger.js

const { format, createLogger, transports } = require('winston');
const moment = require('moment');

// Thanks to luislobo for the workaround to handle multiple parameters - https://github.com/winstonjs/winston/issues/1427#issuecomment-427104223

// Format Object
function formatObject(param) {
  if (param instanceof Object) {
    return JSON.stringify(param);
  }
  return param;
}

// Format splat into message string
const all = format(info => {
  const splat = info[Symbol.for('splat')] || [];
  const message = formatObject(info.message);
  const rest = splat.map(formatObject).join(' ');
  info.message = `${message} ${rest}`;
  return info;
});

// Define the settings for each transport
var options = {
  jsonFile: {
    level: 'info',
    name: 'file.json.info',
    filename: `./logs/${moment().format('YYYY-MM-DD')}-info.log`,
    handleExceptions: true,
    json: true,
    maxsize: 5242880, // 5MB
    maxFiles: 100,
    format: format.combine(
      all(),
      format.timestamp(),
      format.printf(info => {
        return `{"timestamp":"${info.timestamp}","level":"${info.level}","message":"${formatObject(info.message)}"}`;
      })
    )
  },
  prettyFile: {
    level: 'debug',
    name: 'file.pretty.info',
    filename: `./logs/${moment().format('YYYY-MM-DD')}-info.log`,
    handleExceptions: true,
    maxsize: 5242880, // 5MB
    maxFiles: 100,
    format: format.combine(
      all(),
      format.timestamp({
        format: 'YYYY-MM-DD HH:mm:ss.SSS'
      }),
      format.align(),
      format.printf(info => {
        return `${info.timestamp} ${info.level}: ${formatObject(info.message)}`;
      })
    )
  },
  errorFile: {
    level: 'error',
    name: 'file.json.error',
    filename: `./logs/${moment().format('YYYY-MM-DD')}-error.log`,
    handleExceptions: true,
    maxsize: 5242880, // 5MB
    maxFiles: 100,
    format: format.combine(
      all(),
      format.timestamp({
        format: 'YYYY-MM-DD HH:mm:ss.SSS'
      }),
      format.align(),
      format.printf(info => {
        return `${info.timestamp} ${info.level}: ${formatObject(info.message)}`;
      })
    )
  },
  console: {
    level: 'debug',
    handleExceptions: true,
    format: format.combine(
      all(),
      format.timestamp({
        format: 'YYYY-MM-DD HH:mm:ss.SSSZZ'
      }),
      format.colorize(),
      format.align(),
      format.printf(info => {
        return `${info.timestamp} ${info.level}: ${formatObject(info.message)}`;
      })
    )
  }
};

// instantiate a new Winston Logger with the settings defined above
let logger = new createLogger({
  transports: [
    // new transports.File(options.jsonFile),
    new transports.File(options.prettyFile),
    new transports.File(options.errorFile),
    new transports.Console(options.console)
  ],
  exitOnError: false
});

// create a stream object with a 'write' function that will be used by `morgan`
logger.stream = {
  write: function(message, encoding) {
    // morgn is set to only log errors in production
    process.env.NODE_ENV !== 'production'
      ? logger.info(message.replace(/^\s+|\s+$/g, '')) // prevent 2 new lines being inserted (removes \r\n)
      : logger.error(message);
   }
};

// Log routes with morgan - this goes in app.js
// process.env.NODE_ENV !== 'production'
//   ? app.use(morgan('dev', { stream: logger.stream }))
//   : app.use(
//       morgan('combined', {
//         stream: logger.stream,
//         // Only log error messages
//         skip: function(req, res) {
//           return res.statusCode < 400;
//         }
//       })
//     );

module.exports = logger;