adsl

Another dead simple logger inspired by the awesome console-log-level.

A dead simple logger. Will log to STDOUT or STDERR depending on the chosen log level. It uses console.info, console.warn and console.error and hence supports the same API.

## Log levels sets supported

npm (default)

{ error: 0, warn: 1, info: 2, verbose: 3, debug: 4, silly: 5 }

console-log-level:

{ fatal: 0, error: 1, warn: 2, info: 3, debug: 4 }

rfc5424:

{ emerg: 0, alert: 1, crit: 2, error: 3, warning: 4, notice: 5, info: 6, debug: 7 }

Installation

npm install adsl

Example usage

// example.js
const adsl = require('adsl')
const colors = require('colors')
const fs = require('fs')
const os = require('os')

function colorsTransport (styles, msg, shouldLog, lvl, lvlIndex) {
  if (colors.supportsColor && styles[lvl]) {
    msg = styles[lvl](msg)
  }
  return adsl.defaultTransport(msg, shouldLog, lvl, lvlIndex)
}

function streamTransport (wstream, msg, shouldLog, lvl, lvlIndex) {
  wstream.write(`${lvlIndex} ${new Date()} ${msg}${os.EOL}`)
}

var logWriteStream = fs.createWriteStream('log.txt')

const log = adsl({
  level: 'info',
  prefix(level) {
    return level.toUpperCase()
  },
  transport: [
    streamTransport.bind(null, logWriteStream),
    colorsTransport.bind(null, {
      trace: colors.grey,
      debug: colors.grey,
      info: colors.cyan,
      warn: colors.red,
      error: colors.bgRed,
      fatal: colors.bgRed
    })
  ]
})

log.info('current level:', log.level, log.levelIndex)
log.info('visible')
log.debug('invisible')

log.level = 'debug'

log.info('current level:', log.level, log.levelIndex)
log.info('foo')
log.debug('bar')

logWriteStream.end(os.EOL)

Options

Configure the logger by passing an options object:

var log = require('adsl')({
  level: 'info',
  levels: 'npm',
  prefix: function (level) {
    return level.toUpperCase()
  },
  defaultTransport: function (msg, shouldLog, lvl, lvlIndex) {
    if (shouldLog) {
      console.log(lvlIndex, lvl, msg)
    }
  }
})

level

A string to specify the log level.

Defaults to : adsl.defaultLevel = "info"

levels

An string to specify the log levels set used.

Defaults to: adsl.defaultLevels = "npm"

prefix

Specify this option if you want to set a prefix for all log messages. This must be a string or a function that returns a string.

transport

Function called by the logger at each logging operation. This must be a function or an array of functions.

Defaults to : adsl.defaultTransport =

function (msg, shouldLog, lvl, lvlIndex) {
  shouldLog &&
    (console[ADSL.outputMap[lvl] || lvl] || console.log).call(console, msg)
}

License

MIT