fix(action-bar): NativeScript#5743 navController may be null (NativeScript#6029)

DickSmith · tsonevn · commit 324fdcebcdd1 · 2018-07-10T13:22:30.000+03:00
* fix(action-bar): NativeScript#5743 navController may be null From my own Crashlytics: `stderr: file:///app/vendor.js:1:860568: JS ERROR TypeError: null is not an object (evaluating 'a.viewControllers')` ``` file:///app/vendor.js:1:860489 var l,p=a.viewControllers.indexOfObject(n);if(p>0&&p<a.viewControllers.count&&(t=a.viewControllers[p-1]),t) ``` which corresponds to: https://github.com/NativeScript/NativeScript/blob/2fc1d8a8d4cf64e98eb98296e21564ac9b508f95/tns-core-modules/ui/action-bar/action-bar.ios.ts#L132 further up `navController` is checked for truthiness: https://github.com/NativeScript/NativeScript/blob/2fc1d8a8d4cf64e98eb98296e21564ac9b508f95/tns-core-modules/ui/action-bar/action-bar.ios.ts#L119 So applying same logic. * Adjusted per request
diff --git a/tns-core-modules/ui/action-bar/action-bar.ios.ts b/tns-core-modules/ui/action-bar/action-bar.ios.ts
@@ -116,7 +116,12 @@ export class ActionBar extends ActionBarBase {
         const viewController = (<UIViewController>page.ios);
         const navigationItem: UINavigationItem = viewController.navigationItem;
         const navController = <UINavigationController>viewController.navigationController;
-        const navigationBar = navController ? navController.navigationBar : null;
+
+        if (!navController) {
+            return;
+        }
+
+        const navigationBar = navController.navigationBar;
         let previousController: UIViewController;
 
         // Set Title
@@ -377,4 +382,4 @@ export class ActionBar extends ActionBarBase {
             this.updateFlatness(navBar);
         }
     }
-}
+}
