logger.js

var colors = require('colors'),
	U = require('./utils');

exports.TRACE = 4;
exports.DEBUG = 3;
exports.INFO = 2;
exports.WARN = 1;
exports.ERROR = 0;
exports.NONE = -1;
exports.logLevel = exports.TRACE;
exports.stripColors = false;
exports.showTimestamp = false;

exports.trace = function(msg) {
	if (exports.logLevel >= exports.TRACE) { printMessage(msg, 'trace', 'grey'); }
};

exports.debug = function(msg) {
	if (exports.logLevel >= exports.DEBUG) { printMessage(msg, 'debug', 'cyan'); }
};

exports.info = function(msg) {
	if (exports.logLevel >= exports.INFO) { printMessage(msg, 'info', 'white'); }
};

exports.warn = function(msg) {
	if (exports.logLevel >= exports.WARN) { printMessage(msg, 'warn', 'yellow'); }
};

exports.error = function(msg) {
	if (exports.logLevel >= exports.ERROR) { printMessage(msg, 'error', 'red'); }
};

// Private functions and members
var levels = ['info', 'debug', 'error', 'warn', 'trace'];
var has = function(array, item) {
	var len = array.length;
	for (var i = 0; i < len; i++) {
		if (array[i] === item) {
			return true;
		}
	}
	return false;
};
var isArray = function(object) {
	return Object.prototype.toString.call(object) === '[object Array]';
};

var formattedDate = function() {
	var date = new Date();
	var pad = function(val) {
		val += '';
		return val.length < 2 ? '0' + val : val;
	};
	return date.getFullYear() + '-' + pad(date.getMonth() + 1) + '-' + pad(date.getDate()) + ' ' +
		pad(date.getHours()) + ':' + pad(date.getMinutes()) + ':' + pad(date.getSeconds());
};

var printMessage = function(msg, level, color) {
	// Validate arguments
	msg = msg || '';
	level = level || 'info';
	level = has(levels, level) ? level : 'info';
	color = color || 'white';

	// Have to wrap in a function to avoid "Illegal invocation" error on android
	var logFunc = function(msg) {
		(level === 'debug' || level === 'trace' ? console.log : console[level])(msg);
	};

	function printLine(line) {
		if (isArray(line)) {
			for (var i = 0; i < line.length; i++) {
				printLine(line[i]);
			}
		} else {
			var tag = (exports.showTimestamp ? formattedDate() + ' -- ' : '') + '[' +
				level.toUpperCase() + '] ';
			var str = tag.grey + (line || '')[color];
			if (exports.stripColors) { str = U.stripColors(str); }
			logFunc(str);
		}
	}
	printLine(msg);
};