Add isBackgroundLoad property on page context (#2286)

* Add isBackgroundLoad for pageInfo context

* Added isBackgroundLoad property under page for app context.

The property indicates that the app is loading in the background as part
of an opt-in performance enhancement.

---------

Co-authored-by: jadahiya-MSFT <95651173+jadahiya-MSFT@users.noreply.github.com>

change/@microsoft-teams-js-2884d1fc-c964-4e5b-858b-3d946100c192.json

@@ -0,0 +1,7 @@
+{
+  "type": "minor",
+  "comment": "Added a new page property (isBackgroundLoad) for app context. This will be an indicator that the app is being loaded in the background.",
+  "packageName": "@microsoft/teams-js",
+  "email": "helentsang@microsoft.com",
+  "dependentChangeType": "patch"
+}

packages/teams-js/src/public/app.ts

@@ -472,6 +472,12 @@ export namespace app {
      */
     isMultiWindow?: boolean;
 
+    /**
+     * Indicates whether the page is being loaded in the background as
+     * part of an opt-in performance enhancement.
+     */
+    isBackgroundLoad?: boolean;
+
     /**
      * Source origin from where the page is opened
      */
@@ -985,6 +991,7 @@ function transformLegacyContextToAppContext(legacyContext: LegacyContext): app.C
       subPageId: legacyContext.subEntityId,
       isFullScreen: legacyContext.isFullScreen,
       isMultiWindow: legacyContext.isMultiWindow,
+      isBackgroundLoad: legacyContext.isBackgroundLoad,
       sourceOrigin: legacyContext.sourceOrigin,
     },
     user: {

packages/teams-js/src/public/interfaces.ts

@@ -668,6 +668,14 @@ export interface Context {
    */
   isMultiWindow?: boolean;
 
+  /**
+   * @deprecated
+   * As of 2.0.0, please use {@link app.PageInfo.isBackgroundLoad | app.Context.page.isBackgroundLoad} instead
+   *
+   * Indication whether the tab is being loaded in the background
+   */
+  isBackgroundLoad?: boolean;
+
   /**
    * @deprecated
    * As of 2.0.0, please use {@link app.AppInfo.iconPositionVertical | app.Context.app.iconPositionVertical} instead

packages/teams-js/test/public/app.spec.ts

@@ -553,6 +553,7 @@ describe('Testing app capability', () => {
             userClickTime: 2222,
             userFileOpenPreference: FileOpenPreference.Inline,
             isMultiWindow: true,
+            isBackgroundLoad: true,
             frameContext: context,
             appLaunchId: 'appLaunchId',
             userDisplayName: 'someTestUser',
@@ -585,6 +586,7 @@ describe('Testing app capability', () => {
               sourceOrigin: 'www.origin.com',
               frameContext: context,
               isMultiWindow: true,
+              isBackgroundLoad: true,
             },
             user: {
               id: 'someUserObjectId',