1.2.0 • Public • Published


A thin wrapper on the debug logging package that allows levels to appear customized for your package.


I didn't like to enter prefix:level where prefix was required to prevent name conflicts because multiple packages might be using the debug package. debug-custom is a thin wrapper around debug that allows the user to hide whatever prefix is used to prevent conflicts. debug-custom also makes it easier to add and remove debug levels dynamically under program control.

The user experience

Using debug the package prefix must be repeated for each log level:

export DEBUG=my-app:error,my-app:warn,my-app:info

and, in code:

const debug = require('debug')

const logError = debug('my-app:error')
const logWarn = debug('my-app:warn')
const logInfo = debug('my-app:info')

Using debug-custom the package prefix is invisible:

export MYAPP=error,warn,info

in code,

const DebugCustom = require ('debug-custom')
// specify the prefix and options, default enabled settings are 'error,warn'.
const logger = new DebugCustom('my-app', {defaultLevels: process.env.MYAPP_LOG_SETTINGS})

const logError = logger.make('error')
const logWarn = logger.make('warn')
const logInfo = logger.make('info')

Added benefits

And, if you want to enable or disable levels via API, just use


If you want to set absolutely (not adding or removing)

const previous = logger.logLevel
logger.logLevel = 'error'
// do some stuff
logger.logLevel = previous

You can also set logLevel to an array if you want.

Final notes

If you need access to the instance of debug used it's available as logger.debug. This can come in handy for testing.

The prefix used to instantiate the CustomDebug class should not conflict with other packages using debug, so try to make yours unique. You won't see it unless you look at the DEBUG environment variable.

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npm i debug-custom

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  • bmacnaughton