index.js

var chalk = require('chalk')
var stacktrace = require('stack-trace')
var path = require('path')

var defaults = {
	'logLevel': 4,
	'status': true,
	'locLength': 12,
	'dateFormat': '[hh:mm:ss]',
	'client': typeof window !== 'undefined',
	'detectFunctions': true,
	'customName': false,
	'colour': {
		error:    chalk.red,    // (0)
		warning:  chalk.yellow, // (1)
		success:  chalk.green,  // (2)
		log:      chalk.gray,   // (3)
		info:     chalk.gray,   // (4)
		date:     chalk.cyan,
		file:     chalk.yellow,
		function: chalk.green
	}
}

function Logger(options) {
	options = options || {}

	for (var option in defaults) {
		this[option] = options[option] ||  defaults[option]
	}

	if (options.customName) this.customName = this.pad(options.customName)
}

Logger.prototype.pad = function(name) {
	while (name.length < this.locLength) name += ' '
	return name
}

Logger.prototype.date = function() {
	var date = new Date()
	var parts = {
		hh: String('00' + date.getHours()).slice(-2),
		mm: String('00' + date.getMinutes()).slice(-2),
		ss: String('00' + date.getSeconds()).slice(-2),
		dd: String('00' + date.getDate()).slice(-2),
		yyyy: String('0000' + date.getFullYear()).slice(-4),
		MM: String('00' + (date.getMonth() + 1)).slice(-2),
	}

	var keys = Object.keys(parts)
	var format = this.dateFormat

	for (var i = 0; i < keys.length; i++) {
		format = format.replace(keys[i], parts[keys[i]])
	}

	return format
}

Logger.prototype.capitalise = function(string) {
	return string.charAt(0).toUpperCase() + string.slice(1);
}

Logger.prototype.error   = function() { if (this.logLevel >= 0) this.print(arguments, 'error')   }
Logger.prototype.warning = function() { if (this.logLevel >= 1) this.print(arguments, 'warning') }
Logger.prototype.success = function() { if (this.logLevel >= 2) this.print(arguments, 'success') }
Logger.prototype.log     = function() { if (this.logLevel >= 3) this.print(arguments, 'log')     }
Logger.prototype.info    = function() { if (this.logLevel >= 4) this.print(arguments, 'info')    }

Logger.prototype.print = function(args, level) {
	var date = this.date()

	var args = Object.keys(args).map(function(key) {
	  return args[key]
	})

	var message = []

	for (var i = 0; i < args.length; i++) {
		if (typeof args[i] === 'string' || typeof args[i] === 'number') {
			message.push(args[i])
		} else {
			message.push('\n' + JSON.stringify(args[i], null, 4))
		}
	}

	message = message.join(' ')
	if (message.charAt(0) == '\n') message = message.slice(1)

	if (this.client) {
		console.log(date, message)
		return
	}

	var func, file

	if (this.customName) {
		var file = this.customName
	} else {
		var stack = stacktrace.get()[2]
		if (stack.getFunctionName()) {
			func = this.pad(stack.getFunctionName() + '()')
		} else {
			file = this.pad(path.basename(stack.getFileName()))
		}
	}

	log = level == 'error' ? console.error : console.log
	log(`${this.colour.date(date)} [${func ? this.colour.function(func) : this.colour.file(file)}] ${this.colour[level](message)}`)
}

module.exports = function(options) { return new Logger(options) };