console-stamp

What is console-stamp?

The console-stamp npm package is used to add timestamps to console output in Node.js applications. It enhances the standard console methods (log, info, warn, error) by prefixing them with a timestamp, making it easier to track when specific log entries were made.

What are console-stamp's main functionalities?

Basic Timestamping

This feature adds a basic timestamp to all console log messages. By requiring the console-stamp package and passing the console object to it, all subsequent console.log calls will include a timestamp.

const consoleStamp = require('console-stamp')(console);
console.log('This is a log message.');

Custom Timestamp Format

This feature allows you to customize the format of the timestamp. By passing an options object with a 'format' property, you can specify the desired timestamp format.

const consoleStamp = require('console-stamp')(console, { format: 'yyyy-mm-dd HH:MM:ss.l' });
console.log('This is a log message with a custom format.');

Custom Label

This feature adds a custom label to the log messages. By setting the 'label' property to true in the options object, you can include a label in the log output.

const consoleStamp = require('console-stamp')(console, { label: true });
console.log('This is a log message with a custom label.');

Custom Prefix

This feature allows you to add a custom prefix to the log messages. By setting the 'prefix' property in the options object, you can include a custom prefix in the log output.

const consoleStamp = require('console-stamp')(console, { prefix: '[LOG]' });
console.log('This is a log message with a custom prefix.');

Other packages similar to console-stamp

winston

Winston is a versatile logging library for Node.js that supports multiple transports (e.g., console, file, HTTP). It provides more advanced logging features compared to console-stamp, such as log levels, custom formats, and log rotation.

bunyan

Bunyan is a simple and fast JSON logging library for Node.js. It provides structured logging with JSON output, making it easier to parse and analyze logs. Unlike console-stamp, Bunyan focuses on structured logging rather than just adding timestamps.

log4js

Log4js is a logging library inspired by the Java log4j library. It supports multiple appenders (e.g., console, file, SMTP) and provides flexible configuration options. Log4js offers more comprehensive logging capabilities compared to console-stamp.

README

console-stamp

This module enables you to patch the console's methods in Node.js, to add timestamp prefix based on a given string pattern, and more...

Usage

Install

npm install console-stamp

Patching the console

require('console-stamp')(console, [options]);

console

The global console or custom console.

options {Object|String}

From version 2.0 the second parameter is an object with several options. As a backward compatibillity feature this parameter can be a string containing the pattern.

• options.pattern {String}
  A string with date format based on Javascript Date Format
  Default: 'ddd mmm dd yyyy HH:MM:ss'

• options.formatter {Function}
  A custom date formatter that should return a formmatted date string.

• options.label {Boolean}
  If true it will show the label (LOG | INFO | WARN | ERROR)
  Default: true

• options.labelPrefix {String}
  A custom prefix for the label.
  For an example see Custom prefix and suffix example
  Default: "["

• options.labelSuffix {String}
  A custom suffix for the label.
  For an example see Custom prefix and suffix example
  Default: "]"

• options.include {Array}
  An array containing the methods to include in the patch
  Default: ["log", "info", "warn", "error", "dir", "assert"]

• options.exclude {Array}
  An array containing the methods to exclude in the patch
  Default: [] (none)

• options.disable {Array}
  An array containing the methods to disable in the patch
  Default: [] (none)

• options.level {String}
  A string choosing the most verbose logging function to allow. Ordered/grouped as such: 'log dir', 'info', 'warn assert', 'error'
  Default: log

• options.extend {Object}
  An object describing methods and their associated log level, to extend the existing method <-> log level pairs.
  For an example see Custom methods.

• options.metadata {String/Object/Function}
  Types can be String, Object (interpreted with util.inspect), or Function. See the test-metadata.js for examples.
  Note that metadata can still be sent as the third parameter (as in vesion 1.6) as a backward compatibillity feature, but this is deprecated.
  Default: undefined

• options.stdout {WritableStream}
  A custom stdout to use with custom console.
  Default: process.stdout

• options.stderr {WritableStream}
  A custom stderr to use with custom console.
  Default: options.stdout or process.stdout

• options.colors {Object}
  An object representing a color theme. More info here.

  • options.colors.stamp {String/Array/Function}
    Default: []

  • options.colors.label {String/Array/Function}
    Default: []

  • options.colors.metadata {String/Array/Function}
    Default: []

• options.datePrefix {String}
  A custom prefix for the datestamp.
  For an example see Custom prefix and suffix example
  Default: "["

• options.dateSuffix {String}
  A custom suffix for the datestamp.
  For an example see Custom prefix and suffix example
  Default: "]" Note: To combine colors, bgColors and style, set them as an array like this:

...
    stamp: ['black', 'bgYellow', 'underline']
...

Or chain Chalk functions like this:

...
stamp: require('chalk').red.bgYellow.underline;
...

Note also that by sending the parameter --no-color when you start your node app, will prevent any colors from console.

$ node my-app.js --no-color

Example

// Patch console.x methods in order to add timestamp information
require('console-stamp')(console, { pattern: 'dd/mm/yyyy HH:MM:ss.l' });

console.log('Hello World!');
// -> [26/06/2015 14:02:48.062] [LOG] Hello World!

const port = 8080;
console.log('Server running at port %d', port);
// -> [26/06/2015 16:02:35.325] [LOG] Server running at port 8080

 

console.log('This is a console.log message');
console.info('This is a console.info message');
console.warn('This is a console.warn message');
console.error('This is a console.error message');
console.dir({bar: 'This is a console.dir message'});

Result:

[26/06/2015 12:44:31.777] [LOG]   This is a console.log message
[26/06/2015 12:44:31.777] [INFO]  This is a console.info message
[26/06/2015 12:44:31.779] [WARN]  This is a console.warn message
[26/06/2015 12:44:31.779] [ERROR] This is a console.error message
[26/06/2015 12:44:31.779] [DIR]   { bar: 'This is a console.dir message' }

and

require('console-stamp')(console, {
    metadata: function () {
        return ('[' + process.memoryUsage().rss + ']');
    },
    colors: {
        stamp: 'yellow',
        label: 'white',
        metadata: 'green'
    }
});

console.log('This is a console.log message');
console.info('This is a console.info message');
console.warn('This is a console.warn message');
console.error('This is a console.error message');
console.dir({bar: 'This is a console.dir message'});

Result:

Custom Console [v0.2.4+]

As of version 0.2.4 you can also create a custom console with its own stdout and stderr like this:

const fs = require('fs');
const output = fs.createWriteStream('./stdout.log');
const errorOutput = fs.createWriteStream('./stderr.log');
const logger = new console.Console(output, errorOutput);

console_stamp(logger, {
    stdout: output,
    stderr: errorOutput
});

Everything is then written to the files.

NOTE: If stderr isn't passed, warning and error output will be sent to the given stdout.

Custom Formatter Example

Custom formatter using moment.js

const moment = require('moment');
moment.locale('ja');

require('console-stamp')(console, {
    formatter: function() {
        return moment().format('LLLL');
    }
});

console.log('This is a console.log message');
console.info('This is a console.info message');
console.warn('This is a console.warn message');
console.error('This is a console.error message');
console.dir({bar: 'This is a console.dir message'});

Result:

[2016年5月12日午前11時10分 木曜日] [LOG]   This is a console.log message
[2016年5月12日午前11時10分 木曜日] [INFO]  This is a console.info message
[2016年5月12日午前11時10分 木曜日] [WARN]  This is a console.warn message
[2016年5月12日午前11時10分 木曜日] [ERROR] This is a console.error message
[2016年5月12日午前11時10分 木曜日] [DIR]   { bar: 'This is a console.dir message' }

Custom Methods

The option.extend option enables the extension or modification of the logging methods and their associated log levels:

The default logging methods and their log levels are as follows:

const levelPriorities = {
    log: 4,
    info: 3,
    warn: 2,
    error: 1,
    assert: 2,
    dir: 4
};

Combined with the include option, the extend option enables the usage of custom console logging methods to be used with this module, for example:

// Extending the console object with custom methods
console.debug = function(msg) {
    console.log(msg);
}
console.fatal = function(msg) {
    console.log(msg);
    process.exit(1);
}

// Initialising the output formatter
require('console-stamp')(console, {
    pattern: 'HH:MM:ss',
    extend: {
        debug: 5,
        fatal: 0,
    },
    include: ['debug', 'info', 'warn', 'error', 'fatal'],
    level: 'debug',
});

Note how the log method is omitted from the include list. Because the custom functions call console.log internally, including the log method would print double-formatted output.

Adding Metadata

Types can be string, object (interpreted with util.inspect), or function. See the test-metadata.js for examples.

String example

require('console-stamp')(console, {
    pattern: 'HH:MM:ss.l',
    metadata: '[' + process.pid + ']'
});

console.log('Metadata applied.');

Result:

[26/06/2015 12:44:31.779] [LOG] [7785] Metadata applied.

Function example

const util = require('util');

require('console-stamp')(console, {
    pattern: 'HH:MM:ss.l',
    metadata: function(){ return '[' + (process.memoryUsage().rss) + ']'; });

console.log('Metadata applied.');

Result:

[18:10:30.875] [LOG] [14503936] Metadata applied.

Custom prefix and suffix example

If you don't want to use the default brackets, you can also define your own custom pre- and suffixes like so:

require('console-stamp')(console, {
    datePrefix: '####',
    dateSuffix: '####',
    labelPrefix: '{',
    labelSuffix: '}'
});

console.log('Custom pre- and suffixed log');

Result:

####Fri Sep 15 2017 16:58:29#### {LOG} Custom pre- and suffixed log