5.1.0 • Public • Published


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Laid back debug logging.


npm install snooplogg



  • Built-in and custom log types
  • Ability to snoop on other snooplogg instances nested in dependencies
  • Pipe messages to one or more streams
  • Namespacing
  • Filter messages using the DEBUG (or SNOOPLOGG) environment variable
  • Automatic color selection with brightness range
  • Exports chalk library for your convenience.
  • Similar API to TJ's debug:


debug style:

// app.js

import snooplogg from 'snooplogg';
import http from 'http';

// const debug = require('debug')('http');
const debug = snooplogg('http').log;
const name = 'My App';

debug('booting %o', name);

http.createServer((req, res) => {
	debug(`${req.method} ${req.url}`);
}).listen(3000, () => debug('listening'));
// worker.js

import snooplogg from 'snooplogg';

const a = snooplogg('worker:a');
const b = snooplogg('worker:b');
Or you could do this:

const worker = snooplogg('worker');
const a = worker('a');
const b = worker('b');

function work_a() {
  a('doing lots of uninteresting work');
  setTimeout(work_a, Math.random() * 1000);


function work_b() {
	b('doing some work');
	setTimeout(work_b, Math.random() * 2000);


Standard console usage:

import log from 'snooplogg';

log.trace('bow'); // writes to stdout/stderr if DEBUG matches + all pipes'wow')

Namespace support:

import snooplogg from 'snooplogg';

const log = snooplogg('myapp');'bow', 'wow', 'wow'); // writes to stdout/stderr if DEBUG=myapp + all pipes

Stream output to stdout:

import snooplogg from 'snooplogg';

const log = snooplogg.stdio('yippy yo');'bow', 'wow', 'wow'); // writes to stdout/stderr + all pipes

const log = snooplogg.enable('*')('yippy yay');'bow', 'wow', 'wow'); // writes to stdout/stderr + all pipes

Pipe output to a stream (such as a file or socket):

import snooplogg from 'snooplogg';

const log = snooplogg
	.pipe(someWritableStream);'yippy', 'yo');

Listen for messages from all SnoopLogg instances, even from other dependencies:

import snooplogg, { snoop } from 'snooplogg';


const log = snooplogg('bumpin');

  .info('and to the four');

log.warn(`It's like this`);
log.error('and like that');
log.fatal('and like this');

Custom log types:

import snooplogg, { type } from 'snooplogg';

type('jin', { color: 'cyan' });
type('juice', { color: 'yellow' });

const log = snooplogg();

log.jin('parents ain\'t home');
log.juice('too much drama', true);


import snooplogg from 'snooplogg';

snooplogg.enable('*').console.log('dawg gone');



Creates a namespaced logger as well as defines the global namespaced logger.


Outputs a message using the standard console.log() format syntax.


Allows you to set various instance specific options.

  • colors - (Array) An array of color names to choose from when auto-selecting a color, specifically for rendering the namespace.
  • minBrightness - (Number) The minimum brightness to auto-select a color. Value must be between 0 and 255 as well as less than or equal to the maxBrightness. Defaults to 80.
  • maxBrightness - (Number) The maximum brightness to auto-select a color. Value must be between 0 and 255 as well as greater than or equal to the minBrightness. Defaults to 210.
  • theme - (String) The name of the default theme to use. Defaults to standard.
  • maxBufferSize - (Number) The maximum number of log lines to buffer. Used to flush prior messages to new pipes.

Returns the original SnoopLogg instance.

Enabling Logging

By default, Snooplogg only prints messages if the the DEBUG or SNOOPLOGG environment variables are set.

# macOS and Linux
$ DEBUG=izzle node loggfather.js

# Windows PowerShell
> $Env:DEBUG="izzle" node loggfather.js

# Windows Command Prompt
> set DEBUG=izzle
> node loggfather.js

Note: You may also use the SNOOPLOGG environment variable to avoid conflicts with other libraries that use debug

You can also use any environment variable you want by simply calling enable() before logging.

import snooplogg from 'snooplogg';

// change the global environment variable name

Note: The console log types (info, warn, error, etc) are for display only. snooplogg does not support log level filtering, only namespace filtering via the SNOOPLOGG (or DEBUG) environment variable or by enable().

Global Defaults

SnoopLogg allows you to set defaults using environment variables that apply to all SnoopLogg instances.

  • SNOOPLOGG_COLOR_LIST - A comma-separated list of supported color names.
  • SNOOPLOGG_DEFAULT_THEME - Sets the theme.
  • SNOOPLOGG_MAX_BUFFER_SIZE - Sets the maxBufferSize.
  • SNOOPLOGG_MAX_BRIGHTNESS - Sets the maxBrightness.
  • SNOOPLOGG_MIN_BRIGHTNESS - Sets the minBrightness.




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