[improvement] Refactor helper.js using lodash (faster underscore).

lib/helper.js

@@ -1,3 +1,8 @@
+var _    = require('lodash');
+var fs   = require('fs');
+var path = require('path');
+
+
 var OS = /(iPhone OS|Mac OS X|Windows|Linux)/;
 var OS_MAP = {
   "iPhone OS": "iOS",
@@ -33,24 +38,12 @@ exports.browserFullNameToShort = function(fullName) {
 
 
 exports.isDefined = function(value) {
-  return typeof value !== 'undefined';
-};
-
-
-exports.isFunction = function(value) {
-  return typeof value === 'function';
-};
-
-
-exports.isString = function(value) {
-  return typeof value === 'string';
-};
-
-
-exports.isObject = function(value) {
-  return typeof value === 'object';
+  return !_.isUndefined(value);
 };
 
+exports.isFunction = _.isFunction;
+exports.isString = _.isString;
+exports.isObject = _.isObject;
 
 var ABS_URL = /^https?:\/\//;
 exports.isUrlAbsolute = function(url) {
@@ -89,12 +82,9 @@ exports.arrayRemove = function(collection, item) {
 
 
 exports.merge = function() {
-  return Array.prototype.slice.call(arguments, 0).reduce(function(result, object) {
-    Object.getOwnPropertyNames(object).forEach(function(name) {
-      result[name] = object[name];
-    });
-    return result;
-  }, {});
+  var args = Array.prototype.slice.call(arguments, 0);
+  args.unshift({});
+  return _.merge.apply({}, args);
 };
 
 
@@ -110,20 +100,11 @@ exports.formatTimeInterval = function(time) {
   return str;
 };
 
-
-var identity = function(path) {
-  return path;
-};
-
 var replaceWinPath = function(path) {
   return exports.isDefined(path) ? path.replace(/\\/g, '/') : path;
 };
 
-exports.normalizeWinPath = process.platform === 'win32' ? replaceWinPath : identity;
-
-
-var fs = require('fs');
-var path = require('path');
+exports.normalizeWinPath = process.platform === 'win32' ? replaceWinPath : _.identity;
 
 exports.mkdirIfNotExists = function mkdir(directory, done) {
   // TODO(vojta): handle if it's a file
@@ -137,3 +118,6 @@ exports.mkdirIfNotExists = function mkdir(directory, done) {
     }
   });
 };
+
+// export lodash
+exports._ = _;

package.json

@@ -53,7 +53,8 @@
     "LiveScript": ">= 1.0.1",
     "colors": "~0.6.0-1",
     "dateformat": ">= 1.0.2-1.2.3",
-    "istanbul": "0.1.11"
+    "istanbul": "0.1.11",
+    "lodash": "~0.9.1"
   },
   "devDependencies": {
     "grunt-contrib-jshint": ">= 0.1.0",
@@ -76,4 +77,4 @@
     "node": ">= 0.8.4"
   },
   "version": "0.5.3"
-}
+}