From 480f1bc6c03bce86fb7546ac42616cdea1e3443b Mon Sep 17 00:00:00 2001
From: martinRenou <martin.renou@gmail.com>
Date: Mon, 6 Jan 2020 11:10:15 +0100
Subject: [PATCH] Improve create_view return type

Signed-off-by: martinRenou <martin.renou@gmail.com>
---
 packages/base-manager/src/manager-base.ts | 5 +++--
 packages/base/src/manager.ts              | 4 ++--
 packages/base/src/widget.ts               | 6 ++++--
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/packages/base-manager/src/manager-base.ts b/packages/base-manager/src/manager-base.ts
index f56b43c2f8..88bceefc66 100644
--- a/packages/base-manager/src/manager-base.ts
+++ b/packages/base-manager/src/manager-base.ts
@@ -89,8 +89,9 @@ export abstract class ManagerBase<T> implements IWidgetManager {
      * Make sure the view creation is not out of order with
      * any state updates.
      */
-    create_view(model: DOMWidgetModel, options: any): Promise<DOMWidgetView>;
-    create_view(model: WidgetModel, options = {}): Promise<WidgetView> {
+    create_view<VT extends DOMWidgetView = DOMWidgetView>(model: DOMWidgetModel, options?: any): Promise<VT>;
+    create_view<VT extends WidgetView = WidgetView>(model: WidgetModel, options?: any): Promise<VT>;
+    create_view<VT extends WidgetView = WidgetView>(model: WidgetModel, options = {}): Promise<VT> {
         const viewPromise = model.state_change = model.state_change.then(() => {
             return this.loadClass(model.get('_view_name'),
                 model.get('_view_module'),
diff --git a/packages/base/src/manager.ts b/packages/base/src/manager.ts
index 0745c07cb5..de9e33dc3e 100644
--- a/packages/base/src/manager.ts
+++ b/packages/base/src/manager.ts
@@ -170,8 +170,8 @@ interface IWidgetManager {
      * Make sure the view creation is not out of order with
      * any state updates.
      */
-    create_view(model: DOMWidgetModel, options?: unknown): Promise<DOMWidgetView>;
-    create_view(model: WidgetModel, options?: unknown): Promise<WidgetView>;
+    create_view<VT extends DOMWidgetView = DOMWidgetView>(model: DOMWidgetModel, options?: unknown): Promise<VT>;
+    create_view<VT extends WidgetView = WidgetView>(model: WidgetModel, options?: unknown): Promise<VT>;
 
     /**
      * callback handlers specific to a view
diff --git a/packages/base/src/widget.ts b/packages/base/src/widget.ts
index 3ddbc6b321..9a0a1ad9bf 100644
--- a/packages/base/src/widget.ts
+++ b/packages/base/src/widget.ts
@@ -691,9 +691,11 @@ class WidgetView extends NativeView<WidgetModel> {
     /**
      * Create and promise that resolves to a child view of a given model
      */
-    create_child_view(child_model: WidgetModel, options = {}): Promise<DOMWidgetView> {
+    create_child_view<VT extends DOMWidgetView = DOMWidgetView>(child_model: DOMWidgetModel, options?: any): Promise<VT>;
+    create_child_view<VT extends WidgetView = WidgetView>(child_model: WidgetModel, options?: any): Promise<VT>;
+    create_child_view<VT extends WidgetView = WidgetView>(child_model: WidgetModel, options = {}): Promise<VT> {
         options = { parent: this, ...options};
-        return this.model.widget_manager.create_view(child_model, options)
+        return this.model.widget_manager.create_view<VT>(child_model, options)
             .catch(utils.reject('Could not create child view', true));
     }