colorful/lib/logging.js

/*
 * Nested color logging support for terminal
 * @author: Hsiaoming Yang <lepture@me.com>
 * 
 * Thanks to: https://github.com/lepture/terminal
 *
 */

var util = require('util')
var os = require('os')
var EventEmitter = require('events').EventEmitter
var color = require('./color')
var count = 0

var levels = {
  'debug': 10,
  'info': 20,
  'warn': 30,
  'error': 40,
  'log': 50
}

var colors = {
  debug: color.grey,
  info: color.green,
  warn: color.yellow,
  error:color.red 
}
var icons = {
  logIcon: color.cyan('➠ '),
  startIcon: color.bold(color.magenta('⚑ ')),
  endIcon: color.cyan('➥ ')
}

function log(context, level, args) {
  if (levels[context.level] > levels[level]) return

  var text = ''
  var stream = process.stdout
  text += Array(count + 1).join('  ')
  if (count) {
    text += icons.logIcon
  }
  if (level === 'warn') {
    text += color.yellow_bg(' WARN ') + ' '
  } else if (level === 'error') {
    text += color.red_bg(' ERROR ') + ' '
    stream = process.stderr
  }
  var colorize = colors[level]
  if (colorize) {
    text += colorize(util.format.apply(context, args)) + os.EOL
  } else {
    text += util.format.apply(context, args) + os.EOL
  }
  stream.write(text)
}

function Logging(level) {
  this.level = level || 'info'
}
Logging.prototype.__proto__ = EventEmitter.prototype
Logging.prototype.start = function() {
    if (levels[this.level] > 25) return;

    var text = Array(count + 1).join('  ')
    text += icons.startIcon
    text += color.bold(util.format.apply(this, arguments)) + os.EOL
    process.stdout.write(text)
    count += 1
    this.emit('logging-start')
}
Logging.prototype.end = function() {
    if (levels[this.level] > 25) return;
    var text = ''
    text += Array(count + 1).join('  ')
    if (count) {
      text += icons.endIcon
    }
    text += util.format.apply(this, arguments) + os.EOL
    process.stdout.write(text)
    count -= 1
    this.emit('logging-end')
}
Logging.prototype.log = function() {
    log(this, 'log', arguments)
}
Logging.prototype.debug = function() {
    log(this, 'debug', arguments)
}
Logging.prototype.info = function() {
    log(this, 'info', arguments)
}
Logging.prototype.warn = function() {
    log(this, 'warn', arguments)
    this.emit('logging-warn')
}
Logging.prototype.error = function() {
    log(this, 'error', arguments)
    this.emit('logging-error')
}
Logging.prototype.config = function(obj) {
    if (obj.verbose) {
      this.level = 'debug'
    }
    if (obj.quiet) {
      this.level = 'warn'
    }
    if (obj.level) {
      this.level = obj.level
    }
    if (obj in colors) {
      this.level = obj
    }
    if (obj.colors) {
      for (var key in obj.colors) {
        (function(key) {
          colors[key] = obj.colors[key]
        })(key)
      }
    }
    if (obj.icons) {
      for (var key in obj.icons) {
        (function(key) {
          icons[key] = obj.icons[key]
        })(key)
      }
    }
}

module.exports = Logging