alfasin/colorful_winston_logger.js

## colorful_winston_logger.js

    const winston = require('winston');
    const { format } = winston;
    const { combine, colorize, timestamp, printf } = format;

    /**
     * /**
     * Use CallSite to extract filename and number, for more info read: https://v8.dev/docs/stack-trace-api#customizing-stack-traces
     * @param numberOfLinesToFetch - optional, when we want more than one line back from the stacktrace
     * @returns {string|null} filename and line number separated by a colon, if numberOfLinesToFetch > 1 we'll return a string
     * that represents multiple CallSites (representing the latest calls in the stacktrace)
     *
     */
    const getFileNameAndLineNumber = function getFileNameAndLineNumber (numberOfLinesToFetch = 1) {
        const oldStackTrace = Error.prepareStackTrace;

        const boilerplateLines = line => line &&
            line.getFileName() &&
            // in the following line you may want to "play" with adding a '/' as a prefix/postfix to your module name
            (line.getFileName().indexOf('<The Name of This Module>') &&
            (line.getFileName().indexOf('/node_modules/') < 0));

        try {
            // eslint-disable-next-line handle-callback-err
            Error.prepareStackTrace = (err, structuredStackTrace) => structuredStackTrace;
            Error.captureStackTrace(this);
            // we need to "peel" the first CallSites (frames) in order to get to the caller we're looking for
            // in our case we're removing frames that come from logger module or from winston
            const callSites = this.stack.filter(boilerplateLines);
            if (callSites.length === 0) {
                // bail gracefully: even though we shouldn't get here, we don't want to crash for a log print!
                return null;
            }
            const results = [];
            for (let i = 0; i < numberOfLinesToFetch; i++) {
                const callSite = callSites[i];
                let fileName = callSite.getFileName();
                // BASE_DIR_NAME is the path to the project root folder
                const BASE_DIR_NAME = require('path').resolve('.');
                fileName = fileName.includes(BASE_DIR_NAME) ? fileName.substring(BASE_DIR_NAME.length + 1) : fileName;
                results.push(fileName + ':' + callSite.getLineNumber());
            }
            return results.join('\n');
        } finally {
            Error.prepareStackTrace = oldStackTrace;
        }
    };

    function humanReadableFormatter ({ level, message, ...metadata }) {
        const filename = getFileNameAndLineNumber();
        return `[${level}] [${filename}] ${message} ${JSON.stringify(metadata)}`;
    }

    const logger = winston.createLogger({
      transports: [
          new winston.transports.Console({
                level: 'info',
                handleExceptions: true,
                humanReadableUnhandledException: true,
                json: false,
                colorize: { all: true },
                stderrLevels: ['error', 'alert', 'critical', 'bizAlert'],
                format: combine(
                    colorize(),
                    timestamp(),
                    humanReadableFormatter,
                ),
            })
        ]
    });

    logger.info('test print', { a: 1, b: 2 });

	const winston = require('winston');
	const { format } = winston;
	const { combine, colorize, timestamp, printf } = format;

	/**
	* /**
	* Use CallSite to extract filename and number, for more info read: https://v8.dev/docs/stack-trace-api#customizing-stack-traces
	* @param numberOfLinesToFetch - optional, when we want more than one line back from the stacktrace
	* @returns {string\|null} filename and line number separated by a colon, if numberOfLinesToFetch > 1 we'll return a string
	* that represents multiple CallSites (representing the latest calls in the stacktrace)
	*
	*/
	const getFileNameAndLineNumber = function getFileNameAndLineNumber (numberOfLinesToFetch = 1) {
	const oldStackTrace = Error.prepareStackTrace;

	const boilerplateLines = line => line &&
	line.getFileName() &&
	// in the following line you may want to "play" with adding a '/' as a prefix/postfix to your module name
	(line.getFileName().indexOf('<The Name of This Module>') &&
	(line.getFileName().indexOf('/node_modules/') < 0));

	try {
	// eslint-disable-next-line handle-callback-err
	Error.prepareStackTrace = (err, structuredStackTrace) => structuredStackTrace;
	Error.captureStackTrace(this);
	// we need to "peel" the first CallSites (frames) in order to get to the caller we're looking for
	// in our case we're removing frames that come from logger module or from winston
	const callSites = this.stack.filter(boilerplateLines);
	if (callSites.length === 0) {
	// bail gracefully: even though we shouldn't get here, we don't want to crash for a log print!
	return null;
	}
	const results = [];
	for (let i = 0; i < numberOfLinesToFetch; i++) {
	const callSite = callSites[i];
	let fileName = callSite.getFileName();
	// BASE_DIR_NAME is the path to the project root folder
	const BASE_DIR_NAME = require('path').resolve('.');
	fileName = fileName.includes(BASE_DIR_NAME) ? fileName.substring(BASE_DIR_NAME.length + 1) : fileName;
	results.push(fileName + ':' + callSite.getLineNumber());
	}
	return results.join('\n');
	} finally {
	Error.prepareStackTrace = oldStackTrace;
	}
	};

	function humanReadableFormatter ({ level, message, ...metadata }) {
	const filename = getFileNameAndLineNumber();
	return `[${level}] [${filename}] ${message} ${JSON.stringify(metadata)}`;
	}

	const logger = winston.createLogger({
	transports: [
	new winston.transports.Console({
	level: 'info',
	handleExceptions: true,
	humanReadableUnhandledException: true,
	json: false,
	colorize: { all: true },
	stderrLevels: ['error', 'alert', 'critical', 'bizAlert'],
	format: combine(
	colorize(),
	timestamp(),
	humanReadableFormatter,
	),
	})
	]
	});

	logger.info('test print', { a: 1, b: 2 });