From 89b737c940ecdf364662108c00749ae002750b29 Mon Sep 17 00:00:00 2001
From: Vidar Tonaas Fauske <vidartf@gmail.com>
Date: Fri, 9 Aug 2019 17:50:08 +0100
Subject: [PATCH 1/2] Make vdom-ext dependencies optional

---
 packages/vdom-extension/src/index.ts | 63 +++++++++++++++-------------
 1 file changed, 34 insertions(+), 29 deletions(-)

diff --git a/packages/vdom-extension/src/index.ts b/packages/vdom-extension/src/index.ts
index 682cd834130a..62894e24d840 100644
--- a/packages/vdom-extension/src/index.ts
+++ b/packages/vdom-extension/src/index.ts
@@ -34,14 +34,15 @@ const FACTORY_NAME = 'VDOM';
 
 const plugin: JupyterFrontEndPlugin<IVDOMTracker> = {
   id: '@jupyterlab/vdom-extension:factory',
-  requires: [IRenderMimeRegistry, INotebookTracker, ILayoutRestorer],
+  requires: [IRenderMimeRegistry],
+  optional: [INotebookTracker, ILayoutRestorer],
   provides: IVDOMTracker,
   autoStart: true,
   activate: (
     app: JupyterFrontEnd,
     rendermime: IRenderMimeRegistry,
-    notebooks: INotebookTracker,
-    restorer: ILayoutRestorer
+    notebooks: INotebookTracker | null,
+    restorer: ILayoutRestorer | null
   ) => {
     const tracker = new WidgetTracker<MimeDocument>({
       namespace: 'vdom-widget'
@@ -57,23 +58,25 @@ const plugin: JupyterFrontEndPlugin<IVDOMTracker> = {
       0
     );
 
-    notebooks.widgetAdded.connect((sender, panel) => {
-      // Get the notebook's context and rendermime;
-      const {
-        context,
-        content: { rendermime }
-      } = panel;
-
-      // Add the renderer factory to the notebook's rendermime registry;
-      rendermime.addFactory(
-        {
-          safe: false,
-          mimeTypes: [MIME_TYPE],
-          createRenderer: options => new RenderedVDOM(options, context)
-        },
-        0
-      );
-    });
+    if (notebooks) {
+      notebooks.widgetAdded.connect((sender, panel) => {
+        // Get the notebook's context and rendermime;
+        const {
+          context,
+          content: { rendermime }
+        } = panel;
+
+        // Add the renderer factory to the notebook's rendermime registry;
+        rendermime.addFactory(
+          {
+            safe: false,
+            mimeTypes: [MIME_TYPE],
+            createRenderer: options => new RenderedVDOM(options, context)
+          },
+          0
+        );
+      });
+    }
 
     app.docRegistry.addFileType({
       name: 'vdom',
@@ -102,15 +105,17 @@ const plugin: JupyterFrontEndPlugin<IVDOMTracker> = {
     // Add widget factory to document registry.
     app.docRegistry.addWidgetFactory(factory);
 
-    // Handle state restoration.
-    void restorer.restore(tracker, {
-      command: 'docmanager:open',
-      args: widget => ({
-        path: widget.context.path,
-        factory: FACTORY_NAME
-      }),
-      name: widget => widget.context.path
-    });
+    if (restorer) {
+      // Handle state restoration.
+      void restorer.restore(tracker, {
+        command: 'docmanager:open',
+        args: widget => ({
+          path: widget.context.path,
+          factory: FACTORY_NAME
+        }),
+        name: widget => widget.context.path
+      });
+    }
 
     return tracker;
   }

From 86ada79dcbd1243e65bf1417308a46bb3e9f4713 Mon Sep 17 00:00:00 2001
From: Vidar Tonaas Fauske <vidartf@gmail.com>
Date: Fri, 9 Aug 2019 17:53:34 +0100
Subject: [PATCH 2/2] strictNullCheck tweak

---
 packages/vdom-extension/src/index.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/vdom-extension/src/index.ts b/packages/vdom-extension/src/index.ts
index 62894e24d840..8a781ee03d37 100644
--- a/packages/vdom-extension/src/index.ts
+++ b/packages/vdom-extension/src/index.ts
@@ -90,7 +90,7 @@ const plugin: JupyterFrontEndPlugin<IVDOMTracker> = {
       dataType: 'json',
       rendermime,
       name: FACTORY_NAME,
-      primaryFileType: app.docRegistry.getFileType('vdom'),
+      primaryFileType: app.docRegistry.getFileType('vdom')!,
       fileTypes: ['vdom', 'json'],
       defaultFor: ['vdom']
     });