my winston logger

my_winston_logger.js

const winston = require('winston');
require('winston-daily-rotate-file');

// can replace with values on configuration
const LOG_CONSOLE_LEVEL = 'debug';
const LOG_CONSOLE_JSON = true;
const LOG_FILE_LEVEL = 'info';
const LOG_FILE_NAME = 'VirtualWorkers-%DATE%.log';

// Winston Daily Rotate File : https://github.com/winstonjs/winston-daily-rotate-file
let rotatedTransport = new (winston.transports.DailyRotateFile)({
    level: LOG_FILE_LEVEL,
    dirname: './log',
    filename: LOG_FILE_NAME,
    datePattern: 'YYYY-MM-DD-HH',
    zippedArchive: true,
    maxSize: '20m',
    maxFiles: '50',
    format: winston.format.combine(winston.format.timestamp(), winston.format.json())
});
rotatedTransport.on('rotate', function (oldFilename, newFilename) {
    logger.info('logfile rotated, oldFileName: ' + oldFilename + ', newFileName' + newFilename);
});

// Winston Console Transports
// https://github.com/winstonjs/winston/blob/master/docs/transports.md
let consoleTransport = new winston.transports.Console({
    format: winston.format.combine(
        winston.format.colorize(),
        winston.format.align(),
        winston.format.timestamp(),
        winston.format.printf((info) => {
            const {
                timestamp, level, message, ...args
            } = info;
            const ts = timestamp.replace('T', ' ');
            return `${ts} [${level}]: ${message} ${Object.keys(args).length && LOG_CONSOLE_JSON ? '\n' + prettyJ(args) : ''}`;
        })
    ),
    level: LOG_CONSOLE_LEVEL
});

const logger = winston.createLogger({
    levels: winston.config.syslog.levels,
    transports: [
        consoleTransport,
        rotatedTransport
    ]
});

// colorize stringified json on terminal
function prettyJ(json) {
    if (typeof json !== 'string') {
        json = JSON.stringify(json, undefined, 2);
    }
    return json.replace(/("(\\u[a-zA-Z0-9]{4}|\\[^u]|[^\\"])*"(\s*:)?|\b(true|false|null)\b|-?\d+(?:\.\d*)?(?:[eE][+-]?\d+)?)/g,
        function (match) {
            let cls = "\x1b[36m";
            if (/^"/.test(match)) {
                if (/:$/.test(match)) {
                    cls = "\x1b[34m";
                } else {
                    cls = "\x1b[32m";
                }
            } else if (/true|false/.test(match)) {
                cls = "\x1b[35m";
            } else if (/null/.test(match)) {
                cls = "\x1b[31m";
            }
            return cls + match + "\x1b[0m";
        }
    );
}

function shortHands(logger) {
    const mapping = {
        en: 'emerg',
        a: 'alert',
        c: 'crit',
        e: 'error',
        w: 'warning',
        n: 'notice',
        i: 'info',
        d: 'debug'
    };
    Object.entries(mapping).forEach((item) => {
        // logger[item[0]] = logger.log(item[1], ...args);
        logger[item[0]] = logger[item[1]];
    })
}

shortHands(logger);

module.exports = logger;