Add copyFile, minFile, and writeFile to lib/common/util.js.

lib/main/build-dist.js

@@ -2,10 +2,9 @@
 
 var _ = require('lodash'),
     async = require('async'),
-    fs = require('fs-extra'),
     path = require('path');
 
-var minify = require('../common/minify.js');
+var util = require('../common/util');
 
 var basePath = path.join(__dirname, '..', '..'),
     distPath = path.join(basePath, 'dist'),
@@ -24,8 +23,8 @@ function onComplete(error) {
 
 function build() {
   async.series([
-    _.partial(fs.copy, baseLodash, distLodash),
-    _.partial(minify, distLodash)
+    util.copyFile(baseLodash, distLodash),
+    util.minFile(distLodash)
   ], onComplete);
 }