extract tar extraction code

lib/pipeline/npm.js

@@ -2,9 +2,6 @@
 // TODO: this is horrible and needs to be refactored ASAP
 let utils = require('../utils/utils.js');
 let fs = require('../core/fs.js');
-let o_fs = require('fs-extra');
-
-var tar = require('tar');
 
 class Npm {
 
@@ -46,19 +43,14 @@ class Npm {
           self.logger.info("downloading " + packageName + " " + version + "....");
 
           utils.downloadFile(fileLocation, packageDirectory + "/" + packageName + ".js", function() {
-            o_fs.createReadStream(packageDirectory + "/" + packageName + ".js").pipe(
-              tar.x({
-                strip: 1,
-                C: packageDirectory
-              }).on('end', function() {
+            utils.extractTar(packageDirectory + "/" + packageName + ".js", packageDirectory, function() {
                 if (returnContent) {
                   let distFile = packageDirectory + packageName + ".js";
                   callback(fs.readFileSync(distFile).toString());
                 } else {
                   callback(packageDirectory);
                 }
-              })
-            );
+            });
           });
         }
 
@@ -77,19 +69,14 @@ class Npm {
           self.logger.info("downloading " + packageName + " " + version + "....");
 
           utils.downloadFile(tarball, packageDirectory + "/downloaded_package.tgz", function() {
-            o_fs.createReadStream(packageDirectory + '/downloaded_package.tgz').pipe(
-              tar.x({
-                strip: 1,
-                C: packageDirectory
-              }).on('end', function() {
+            utils.extractTar(packageDirectory + "/downloaded_package.tgz", packageDirectory, function() {
                 if (returnContent) {
                   let distFile = packageDirectory + returnContent;
                   callback(fs.readFileSync(distFile).toString());
                 } else {
                   callback(packageDirectory);
                 }
-              })
-            );
+            });
           });
         }
       }

lib/utils/utils.js

@@ -4,6 +4,7 @@ let merge = require('merge');
 let http = require('follow-redirects').http;
 let https = require('follow-redirects').https;
 let shelljs = require('shelljs');
+var tar = require('tar');
 
 //let fs = require('../core/fs.js');
 let o_fs = require('fs-extra');
@@ -92,6 +93,17 @@ function downloadFile(url, dest, cb) {
   });
 }
 
+function extractTar(filename, packageDirectory, cb) {
+  o_fs.createReadStream(filename).pipe(
+    tar.x({
+      strip: 1,
+      C: packageDirectory
+    }).on('end', function() {
+      cb();
+    })
+  );
+}
+
 module.exports = {
   joinPath: joinPath,
   filesMatchingPattern: filesMatchingPattern,
@@ -104,5 +116,6 @@ module.exports = {
   cd: cd,
   sed: sed,
   exit: exit,
-  downloadFile: downloadFile
+  downloadFile: downloadFile,
+  extractTar: extractTar
 };