fix(overlay): do not dom cache views before overlays

Closes #5483

ionic/components/nav/nav-controller.ts

@@ -990,10 +990,19 @@ export class NavController extends Ion {
       } else {
         // there are no other transitions happening but this one
         // only entering/leaving should show, all others hidden
-        this._views.forEach(view => {
-          let shouldShow = (view === enteringView) || (view === leavingView);
+        // also if a view is an overlay or the previous view is an
+        // overlay then always show the overlay and the view before it
+        var view: ViewController;
+        var shouldShow: boolean;
+
+        for (var i = 0, ii = this._views.length; i < ii; i++) {
+          view = this._views[i];
+          shouldShow = (view === enteringView) ||
+                       (view === leavingView) ||
+                       view.isOverlay ||
+                       (i < ii - 1 ? this._views[i + 1].isOverlay : false);
           view.domCache(shouldShow, this._renderer);
-        });
+        }
       }
 
       // call each view's lifecycle events

ionic/components/nav/test/nav-controller.spec.ts

@@ -477,6 +477,73 @@ export function run() {
         expect(navOptions.animate).toBe(false);
       });
 
+      it('should set domCache true when isAlreadyTransitioning', () => {
+        let enteringView = new ViewController(Page1);
+        let leavingView = new ViewController(Page2);
+        let isAlreadyTransitioning = true;
+        var navOptions: NavOptions = {};
+        var done = () => {};
+        nav._beforeTrans = () => {}; //prevent running beforeTrans for tests
+        nav._renderer = null;
+
+        spyOn(enteringView, 'domCache');
+        spyOn(leavingView, 'domCache');
+
+        nav._postRender(1, enteringView, leavingView, isAlreadyTransitioning, navOptions, done);
+
+        expect(enteringView.domCache).toHaveBeenCalledWith(true, nav._renderer);
+        expect(leavingView.domCache).toHaveBeenCalledWith(true, nav._renderer);
+      });
+
+      it('should set domCache true when isAlreadyTransitioning false for the entering/leaving views', () => {
+        let view1 = new ViewController(Page1);
+        let view2 = new ViewController(Page2);
+        let view3 = new ViewController(Page3);
+        let isAlreadyTransitioning = false;
+        var navOptions: NavOptions = {};
+        var done = () => {};
+        nav._beforeTrans = () => {}; //prevent running beforeTrans for tests
+        nav._renderer = null;
+        nav._views = [view1, view2, view3];
+
+        spyOn(view1, 'domCache');
+        spyOn(view2, 'domCache');
+        spyOn(view3, 'domCache');
+
+        nav._postRender(1, view3, view2, isAlreadyTransitioning, navOptions, done);
+
+        expect(view1.domCache).toHaveBeenCalledWith(false, nav._renderer);
+        expect(view2.domCache).toHaveBeenCalledWith(true, nav._renderer);
+        expect(view3.domCache).toHaveBeenCalledWith(true, nav._renderer);
+      });
+
+      it('should set domCache true when isAlreadyTransitioning false for views when a view has isOverlay=true', () => {
+        let view1 = new ViewController(Page1);
+        let view2 = new ViewController(Page2);
+        let view3 = new ViewController(Page3);
+        let view4 = new ViewController(Page4);
+        let isAlreadyTransitioning = false;
+        var navOptions: NavOptions = {};
+        var done = () => {};
+        nav._beforeTrans = () => {}; //prevent running beforeTrans for tests
+        nav._renderer = null;
+        nav._views = [view1, view2, view3, view4];
+
+        view3.isOverlay = true;
+
+        spyOn(view1, 'domCache');
+        spyOn(view2, 'domCache');
+        spyOn(view3, 'domCache');
+        spyOn(view4, 'domCache');
+
+        nav._postRender(1, view4, view3, isAlreadyTransitioning, navOptions, done);
+
+        expect(view1.domCache).toHaveBeenCalledWith(false, nav._renderer);
+        expect(view2.domCache).toHaveBeenCalledWith(true, nav._renderer);
+        expect(view3.domCache).toHaveBeenCalledWith(true, nav._renderer);
+        expect(view4.domCache).toHaveBeenCalledWith(true, nav._renderer);
+      });
+
     });
 
     describe('_setZIndex', () => {

ionic/components/nav/view-controller.ts

@@ -71,6 +71,11 @@ export class ViewController {
    */
   fireOtherLifecycles: boolean = true;
 
+  /**
+   * @private
+   */
+  isOverlay: boolean = false;
+
   /**
    * @private
    */