Lowercase and trim npm package names for templates

Nodejs/Product/ProjectWizard/NodejsPackageParametersExtension.cs

@@ -14,23 +14,17 @@
 //
 //*********************************************************//
 
+using System;
 using System.Collections.Generic;
 using System.Text.RegularExpressions;
 using EnvDTE;
 using Microsoft.VisualStudio.TemplateWizard;
-
+
 namespace Microsoft.NodejsTools.ProjectWizard {
     class NodejsPackageParametersExtension : IWizard {
         public void RunStarted(object automationObject, Dictionary<string, string> replacementsDictionary, WizardRunKind runKind, object[] customParams) {
             var projectName = replacementsDictionary["$projectname$"];
-
-            // Remove all leading url-invalid, underscore, and period characters from the string
-            var npmProjectNameTransform = Regex.Replace(projectName, "^[^a-zA-Z0-9-~]*", string.Empty);
-
-            // Replace all invalid characters with a dash
-            npmProjectNameTransform = Regex.Replace(npmProjectNameTransform, "[^a-zA-Z0-9-_~.]", "-");
-
-            replacementsDictionary.Add("$npmsafeprojectname$", npmProjectNameTransform);
+            replacementsDictionary.Add("$npmsafeprojectname$", NormalizeNpmPackageName(projectName));
         }
 
         public void ProjectFinishedGenerating(EnvDTE.Project project) {
@@ -51,6 +45,25 @@ public void BeforeOpeningFile(ProjectItem projectItem) {
 
         public void RunFinished() {
             return;
+        }
+
+        private const int NpmPackageNameMaxLength = 214;
+
+        /// <summary>
+        /// Normalize a project name to be a valid Npm package name: https://docs.npmjs.com/files/package.json#name
+        /// </summary>
+        /// <param name="projectName">Name of a VS project.</param>
+        private static string NormalizeNpmPackageName(string projectName) {
+            // Remove all leading url-invalid, underscore, and period characters
+            var npmProjectNameTransform = Regex.Replace(projectName, "^[^a-zA-Z0-9-~]*", string.Empty);
+
+            // Replace all invalid characters with a dash
+            npmProjectNameTransform = Regex.Replace(npmProjectNameTransform, "[^a-zA-Z0-9-_~.]", "-");
+
+            // Insert hyphens between camelcased sections.
+            npmProjectNameTransform = Regex.Replace(npmProjectNameTransform, "([a-z0-9])([A-Z])", "$1-$2").ToLowerInvariant();
+
+            return npmProjectNameTransform.Substring(0, Math.Min(npmProjectNameTransform.Length, NpmPackageNameMaxLength));
         }
     }
 }