Store users preferred tab in localStorage (#7098)

* Store users preferred tab in localStorage

* PR feedback

Author: khellang

src/NuGetGallery/Scripts/gallery/page-display-package.js

@@ -88,6 +88,22 @@ $(function () {
         $(this).closest('form').submit();
     })
 
+    var storage = window['localStorage'];
+    if (storage) {
+        var key = 'preferred_tab';
+
+        // Restore preferred tab selection from localStorage.
+        var preferredTab = storage.getItem(key);
+        if (preferredTab) {
+            $('#' + preferredTab).tab('show');
+        }
+
+        // Make sure we save the user's preferred tab to localStorage.
+        $('.package-manager-tab').on('shown.bs.tab', function (e) {
+            storage.setItem(key, e.target.id);
+        });
+    }
+
     // Emit a Google Analytics event when the user expands or collapses the Dependencies section.
     if (window.nuget.isGaAvailable()) {
         $("#dependency-groups").on('hide.bs.collapse show.bs.collapse', function (e) {

src/NuGetGallery/Views/Packages/DisplayPackage.cshtml

@@ -110,6 +110,7 @@
 {
     <li role="presentation" class="@(active ? "active" : string.Empty)">
         <a href="#@packageManager.Id" aria-expanded="@(active ? "true" : "false")"
+           id="@packageManager.Id-tab" class="package-manager-tab"
            aria-selected="@(active ? "true" : "false")"
            aria-controls="@packageManager.Id" role="tab" data-toggle="tab"
            title="Switch to tab panel which contains package installation command for @packageManager.Name">