logger

Configurable console logger with support for multiple independent groups.

Install

npm i @haxtra/logger

Usage

Basic

const Logger = require('@haxtra/logger')

const log = Logger()
log.info('Hello world!')
// > 2027-09-20 19:50:57.810 [app|info] Hello world!

Multiple loggers

// equivalent
const apilog = Logger('api')
const apilog = log.spawn('api')

Set name and level at creation time

// equivalent
Logger('api', 'warning')
Logger({group:'api', level:'warning'})

log.spawn('api', 'warning')
log.spawn({group:'api', level:'warning'})

Log arbitrary objects

log.info('Mysterious object', {foo:'bar'})
// > 2027-09-20 19:50:57.810 [app|info] Mysterious object
// > { foo: 'bar' }

Config

Global

Configure global settings

// showing defaults
Logger.config({
	level: 'trace',   // global log level, for instances that follow global setting (see Levels below)
	group: true,      // display group name, ie [app|info] vs [info]
	timestamp: true,  // display timestamps
	milli: true,      // display timestamps with millisecond resolution
	color: true,      // use colors in logging
	icons: false,     // use icons instead of level names, ie [I] vs [info]
})

Global settings can also be changed via logger instance

log.setGlobalConfig(object)

Instance

Set level

log.setLevel(level)

Set global level

log.setGlobalLevel(level)

Change group name

log.setGroup(groupName)

Log Levels

By default, instances have a level of null, and they follow the global setting. But you can, for example, set error as the global level and then trace for a particular instance to get a detailed log from just that one particular module.

// info, logs to stdout
log.trace
log.debug
log.dev
log.success
log.ok
log.info
log.notice

// errors, logs to stderr
log.warning
log.alert
log.error
log.exception
log.critical
log.fatal

Set levels by:

log.setLevel(level)       // instance level
log.setGlobalLevel(level) // global level

Pausing output

Logging can be paused anytime by:

// cycle instance logging
log.pause()
log.resume()

// cycle global logging
log.pauseGlobal()
log.resumeGlobal()

Remove logger

Delete logger instance by:

log.dispose()

Haxxor Tricks

Access underlying state via these objects:

log.$ // active instances
log.localConfig
log.globalConfig

File logging

Currently logger does not support file logging, but you can redirect stdout and stderr to a file, by using the commands below. Note: you might want to disable color output, or strip ansi control codes on the fly with tools like ansi2txt or sed.

# log stdout and stderr to one file
node app.js >> app.log 2>&1

# log stdout and stderr to separate files
node app.js >> stdout.log 2>> stderr.log

License

MIT