logger.js

const winston = require("winston");
const path = require("path");
const rootDir = path.join(__dirname, "../../..");
const colorize = require("winston/lib/winston/config").colorize;
const TSFORMAT = () => (new Date().toISOString());

const transports = process.env.NODE_ENV !== "production"
    ? [new winston.transports.Console({
        level: "debug",
        handleExceptions: true,
        humanReadableUnhandledException: true,
        json: false,
        prettyPrint: true,
        timestamp: TSFORMAT,
        colorize: "all",
        formatter: (data) => {
            let finalResult = "";
            finalResult += `[${data.timestamp()} - ${data.level.toUpperCase()}]: ${data.message}`;
            if (data.meta && Object.keys(data.meta).length) {
                finalResult += data.meta.message + "\n";
                finalResult += data.meta.stack;
            }
            if (data.level !== "info") {
                return colorize(data.level, finalResult);
            } else {
                return finalResult;
            }
        }
    })]
    : [
        new winston.transports.File({
            name: "error",
            level: "error",
            filename: "./logs/error-level.txt",
            handleExceptions: true,
            json: false,
            maxsize: 5242880, //5MB
            maxFiles: 50,
            timestamp: TSFORMAT,
            prettyPrint: true,
            colorize: "all",
            formatter: (data) => {
                let finalResult = "";
                finalResult += `[${data.timestamp()} - ${data.level.toUpperCase()}]: ${data.message}`;
                if (data.meta && Object.keys(data.meta).length) {
                    finalResult += data.meta.message + "\n";
                    finalResult += data.meta.stack;
                }
                if (data.level !== "info") {
                    return colorize(data.level, finalResult);
                } else {
                    return finalResult;
                }
            }
        }),
        new winston.transports.File({
            name: "debug",
            level: "debug",
            filename: "./logs/debug-level.txt",
            handleExceptions: true,
            json: false,
            maxsize: 5242880, //5MB
            maxFiles: 100,
            timestamp: TSFORMAT,
            prettyPrint: true,
            colorize: "all",
            formatter: (data) => {
                let finalResult = "";
                finalResult += `[${data.timestamp()} - ${data.level.toUpperCase()}]: ${data.message}`;
                if (data.meta && Object.keys(data.meta).length) {
                    finalResult += data.meta.message + "\n";
                    finalResult += data.meta.stack;
                }
                if (data.level !== "info") {
                    return colorize(data.level, finalResult);
                } else {
                    return finalResult;
                }
            }
        })
    ];
winston.addColors({
    "debug": "green",
});
const logger = new winston.Logger({
    transports: transports,
    exitOnError: false
});

const formatLogArg = (args) => {
    args = Array.prototype.slice.call(args);
    const stackInfo = getStackInfo(1);
    if (stackInfo) {
        const callee = `[${stackInfo.relativePath}:${stackInfo.line}]`;
        if (typeof (args[0]) === "string") {
            args[0] = `${callee} ${args[0]}`;
        } else {
            args.unshift(callee);
        }
    }
    //Pushing an empty meta object this it's considered a meta
    args.push({});
    return args;
};

const getStackInfo = (stackIndex) => {
    // get call stack, and analyze it
    // get all file, method, and line numbers
    const stackList = (new Error()).stack.split("\n").slice(3);

    // stack trace format:
    // http://code.google.com/p/v8/wiki/JavaScriptStackTraceApi
    // do not remove the regex expresses to outside of this method (due to a BUG in node.js)
    const stackReg = /at\s+(.*)\s+\((.*):(\d*):(\d*)\)/gi;
    const stackReg2 = /at\s+()(.*):(\d*):(\d*)/gi;
    const s = stackList[stackIndex] || stackList[0];
    const sp = stackReg.exec(s) || stackReg2.exec(s);

    if (sp && sp.length === 5) {
        return {
            method: sp[1],
            relativePath: path.relative(rootDir, sp[2]),
            line: sp[3],
            pos: sp[4],
            file: path.basename(sp[2]),
            stack: stackList.join("\n")
        };
    }
};

module.exports.stream = {
    write: (message) => {
        logger.info(message);
    }
};
module.exports.debug = module.exports.log = function() {
    logger.debug.apply(logger, formatLogArg(arguments));
};
module.exports.info = function() {
    logger.info.apply(logger, formatLogArg(arguments));
};
module.exports.warn = function() {
    logger.warn.apply(logger, formatLogArg(arguments));
};
module.exports.error = function() {
    logger.error.apply(logger, formatLogArg(arguments));
};
module.exports.verbose = function() {
    logger.verbose.apply(logger, formatLogArg(arguments));
};