Console-stamp 3.0.0 RC3

This module enables you to patch the console's methods in Node.js, to add prefix based on tokens, and more...

Usage

Install

npm install console-stamp@next

Simple example

This simple example is using the default settings

require( 'console-stamp' )( console );

console.log('Hello, World!');
// -> [10.02.2019 15:37:43.452] [LOG]   Hello, World!

Patching the console

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

console

The global console or custom console.

options {Object|String}

The second parameter is an object with several options. As a feature this parameter can be a string containing the date-format.

• options.format {String}
  A string with date format based on dateformat
  Default: 'dd.mm.yyyy HH:MM:ss.l'

• options.tokens {Object}
  Containing token-functions. See example here.

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

• options.level {String}
  A string choosing the most verbose logging function to allow.
  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.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.stderr

Tokens

There are only two predefined tokens registered by default. These are:

:date([format][,utc])[.color]
:label([padding])[.color]

:date([format][,utc])

• format {String}
  Containing the date format based on dateformat
  Default: 'dd.mm.yyyy HH:MM:ss.l'
• utc {Boolean}
  Set to true will return UTC-time
  Default: false

:label([padding])

• padding {Number}
  The total length of the label, including the brackets and padding
  Default: 7

TODO: How to write custom tokens

Create a custom token

To define your own token, simply add a callback function with the token name to the tokens option. This callback function is expected to return a string. The value returned is then available as ":foo()" in this case:

require( 'console-stamp' )( console, {
    format: ':foo() :label(7)',
    tokens:{
        foo: () => {
            return '[my prefix]';
        }
    }
} );

console.log("Bar")

// > [my prefix] [LOG]   Bar

The token callback function is called with one argument, representing an Object with the following properties:

• method {String}
  The invoked method
• params {Array}
  The token parameters (ex: The token call :label(7) will have params [7])
• tokens {Object}
  All the defined tokens, incl. the defaults
• defaultTokens {Object}
  Only the default tokens, even if it's been redefined in options

Example

Here we are making a custom date token called mydate using moment.js to format the date

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

require( 'console-stamp' )( console, {
    format: ':mydate() :label(7)',
    tokens:{
        mydate: () => {
            return `[${moment().format('LLLL')}]`;
        }
    }
} );

console.log('This is a console.log message');
console.info('This is a console.info message');
console.debug('This is a console.debug message');
console.warn('This is a console.warn message');
console.error('This is a console.error 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] [DEBUG] This is a console.debug 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

Colors and styling

All tokens can have a trailing styling like this:

require( 'console-stamp' )( console, {
    format: ':foo().blue.bgWhite.underline :label(7)',
    tokens:{
        foo: () => {
            return 'bar';
        }
    }
} );

TODO: Color Groups

ex: (foo).yellow

Note 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, { format: ':date(dd/mm/yyyy HH:MM:ss.l) :label' } );

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.debug('This is a console.debug message');
console.warn('This is a console.warn message');
console.error('This is a console.error 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 12:44:31.778] [DEBUG] 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

Custom Console

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);

require('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 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:

levels: {
    error: 1,
    warn: 2,
    info: 3,
    log: 4,
    debug: 4
};

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

// Extending the console with a custom method
console.fatal = function(msg) {
    console.org.error(msg);
    process.exit(1);
}

// Initialising the output formatter
require( 'console-stamp' )( console, {
    extend: {
        fatal: 1
    }
} );

Note how the console.org.error method used in the custom method. This is to prevent circular calls to console.error