Fix npm install after adding entry to..

.. package.json. Without the proper prefix, npm will install the package
to the wrong location and will fail. pass prefix to ask it to install in
the current project's node_modules folder.

src/commands/azure-node.browse-packages.js

@@ -1,4 +1,5 @@
 var fs = require('fs');
+var path = require('path');
 var vscode = require('vscode');
 var npmUserPackages = require('npm-user-packages');
 var jsonEditor = require('../codegen/jsoneditor');
@@ -38,12 +39,16 @@ function updatePackageJsonAndNpmInstall(packageToAdd) {
     jsonEditor.addDependenciesIfRequired(filePath, packages);
     
     // TODO: run npm-install only if package.json was touched
-    var installTask = utils.npmInstall(packages, { global: false });
+    var npmOptions = {
+      prefix: filePath.slice(0, filePath.lastIndexOf(path.sep))
+    };
+
+    var installTask = utils.npmInstall(packages, npmOptions);
     return installTask.then(
-      function onFulfilled(value) {
+      function onFulfilled() {
         vscode.window.setStatusBarMessage(`npm install succeeded for ${packageToAdd}.`);
       },
-      function onRejected(reason) {
+      function onRejected() {
         vscode.window.setStatusBarMessage(`npm install failed for ${packageToAdd}.`);        
       }
     );

src/commands/azure-node.template-deploy.js

@@ -1,4 +1,5 @@
 var fs = require('fs');
+var path = require('path');
 var vscode = require('vscode');
 var codegen = require('../codegen/codgen.template-deploy');
 var jsonEditor = require('../codegen/jsoneditor');
@@ -28,12 +29,16 @@ function updatePackageJsonAndNpmInstall() {
     jsonEditor.addDependenciesIfRequired(filePath, packages);
 
     // TODO: run npm-install only if package.json was touched
-    var installTask = utils.npmInstall(packages, { global: false });
+     var npmOptions = {
+      prefix: filePath.slice(0, filePath.lastIndexOf(path.sep))
+    };
+
+    var installTask = utils.npmInstall(packages, npmOptions);
     return installTask.then(
-      function onFulfilled(value) {
+      function onFulfilled() {
         vscode.window.setStatusBarMessage(`npm install succeeded.`);
       },
-      function onRejected(reason) {
+      function onRejected() {
         vscode.window.setStatusBarMessage(`npm install failed.`);
       }
     );

src/utils.js

@@ -2,6 +2,7 @@ var fs = require('fs');
 var path = require('path');
 var vscode = require('vscode');
 let exec = require('child_process').exec;
+var npm = require('npm');
 
 // checks if there exists a valid installation of NodeJs on this machine
 exports.isNodeInstalled = function isNodeInstalled() {
@@ -73,7 +74,8 @@ exports.npmInstall = function npmInstall(packages, opts) {
     var cmdString = "npm install " + packages.join(" ") + " "
         + (opts.global ? " -g" : "")
         + (opts.save ? " --save" : "")
-        + (opts.saveDev ? " --saveDev" : "");
+        + (opts.saveDev ? " --saveDev" : "")
+        + (opts.prefix ? " --prefix " + opts.prefix : "");
 
     return new Promise(function (resolve, reject) {
         exec(cmdString, { cwd: opts.cwd ? opts.cwd : "/" }, (error) => {
@@ -113,3 +115,24 @@ function getSourceLocation() {
     }
 }
 
+exports.install = function install(pkgName, options) {
+    var promise = new Promise(function (resolve, reject) {
+        if (!options) {
+            reject("options.prefix is required.");
+        }
+
+        npm.load(options, function (err) {
+            if (err) {
+                return reject(err);
+            }
+            npm.commands.install([pkgName + '@latest'], function (err, info) {
+                if (err) {
+                    reject(err);
+                }
+                resolve(info);
+            });
+        });
+    });
+
+    return promise;
+};