Split the JupyterLab extension into plugins that provide the widget manager and register widgets.

This paves the way to having separate extensions that load multiple versions of core widgets, so that ipywidgets 7.x and 8.x can be supported simultaneously, for example.

Author: jasongrout

python/jupyterlab_widgets/src/plugin.ts

@@ -144,7 +144,7 @@ export function registerWidgetManager(
 /**
  * The widget manager provider.
  */
-const plugin: JupyterFrontEndPlugin<base.IJupyterWidgetRegistry> = {
+export const managerPlugin: JupyterFrontEndPlugin<base.IJupyterWidgetRegistry> = {
   id: '@jupyter-widgets/jupyterlab-manager:plugin',
   requires: [IRenderMimeRegistry],
   optional: [
@@ -159,7 +159,6 @@ const plugin: JupyterFrontEndPlugin<base.IJupyterWidgetRegistry> = {
   autoStart: true,
 };
 
-export default plugin;
 
 function updateSettings(settings: ISettingRegistry.ISettings): void {
   SETTINGS.saveState = settings.get('saveState').composite as boolean;
@@ -277,47 +276,6 @@ function activateWidgetExtension(
     ]);
   }
 
-  WIDGET_REGISTRY.push({
-    name: '@jupyter-widgets/base',
-    version: base.JUPYTER_WIDGETS_VERSION,
-    exports: {
-      WidgetModel: base.WidgetModel,
-      WidgetView: base.WidgetView,
-      DOMWidgetView: base.DOMWidgetView,
-      DOMWidgetModel: base.DOMWidgetModel,
-      LayoutModel: base.LayoutModel,
-      LayoutView: base.LayoutView,
-      StyleModel: base.StyleModel,
-      StyleView: base.StyleView,
-      ErrorWidgetView: base.ErrorWidgetView,
-    },
-  });
-
-  WIDGET_REGISTRY.push({
-    name: '@jupyter-widgets/controls',
-    version: JUPYTER_CONTROLS_VERSION,
-    exports: () => {
-      return new Promise((resolve, reject) => {
-        (require as any).ensure(
-          ['@jupyter-widgets/controls'],
-          (require: NodeRequire) => {
-            // eslint-disable-next-line @typescript-eslint/no-var-requires
-            resolve(require('@jupyter-widgets/controls'));
-          },
-          (err: any) => {
-            reject(err);
-          },
-          '@jupyter-widgets/controls'
-        );
-      });
-    },
-  });
-
-  WIDGET_REGISTRY.push({
-    name: '@jupyter-widgets/output',
-    version: OUTPUT_WIDGET_VERSION,
-    exports: { OutputModel, OutputView },
-  });
 
   return {
     registerWidget(data: base.IWidgetRegistryData): void {
@@ -326,6 +284,81 @@ function activateWidgetExtension(
   };
 }
 
+
+/**
+ * The base widgets.
+ */
+export const baseWidgetsPlugin: JupyterFrontEndPlugin<void> = {
+  id: `@jupyter-widgets/jupyterlab-manager:base-${base.JUPYTER_WIDGETS_VERSION}`,
+  requires: [base.IJupyterWidgetRegistry],
+  autoStart: true,
+  activate: (app: JupyterFrontEnd, registry: base.IJupyterWidgetRegistry): void => {
+    registry.registerWidget({
+      name: '@jupyter-widgets/base',
+      version: base.JUPYTER_WIDGETS_VERSION,
+      exports: {
+        WidgetModel: base.WidgetModel,
+        WidgetView: base.WidgetView,
+        DOMWidgetView: base.DOMWidgetView,
+        DOMWidgetModel: base.DOMWidgetModel,
+        LayoutModel: base.LayoutModel,
+        LayoutView: base.LayoutView,
+        StyleModel: base.StyleModel,
+        StyleView: base.StyleView,
+        ErrorWidgetView: base.ErrorWidgetView,
+      },
+    });
+  }
+};
+
+
+/**
+ * The control widgets.
+ */
+export const controlWidgetsPlugin: JupyterFrontEndPlugin<void> = {
+  id: `@jupyter-widgets/jupyterlab-manager:controls-${JUPYTER_CONTROLS_VERSION}`,
+  requires: [base.IJupyterWidgetRegistry],
+  autoStart: true,
+  activate: (app: JupyterFrontEnd, registry: base.IJupyterWidgetRegistry): void => {
+    registry.registerWidget({
+      name: '@jupyter-widgets/controls',
+      version: JUPYTER_CONTROLS_VERSION,
+      exports: () => {
+        return new Promise((resolve, reject) => {
+          (require as any).ensure(
+            ['@jupyter-widgets/controls'],
+            (require: NodeRequire) => {
+              // eslint-disable-next-line @typescript-eslint/no-var-requires
+              resolve(require('@jupyter-widgets/controls'));
+            },
+            (err: any) => {
+              reject(err);
+            },
+            '@jupyter-widgets/controls'
+          );
+        });
+      }
+    });
+  }
+};
+
+/**
+ * The output widget.
+ */
+export const outputWidgetPlugin: JupyterFrontEndPlugin<void> = {
+  id: `@jupyter-widgets/jupyterlab-manager:output-${OUTPUT_WIDGET_VERSION}`,
+  requires: [base.IJupyterWidgetRegistry],
+  autoStart: true,
+  activate: (app: JupyterFrontEnd, registry: base.IJupyterWidgetRegistry): void => {
+    registry.registerWidget({
+      name: '@jupyter-widgets/output',
+      version: OUTPUT_WIDGET_VERSION,
+      exports: { OutputModel, OutputView }
+    });
+  }
+};
+
+export default [managerPlugin, baseWidgetsPlugin, controlWidgetsPlugin, outputWidgetPlugin];
 namespace Private {
   /**
    * A private attached property for a widget manager.