fix(vue): tabs no longer get unmounted when navigating back to a tabs context (#24337)

resolves #24332

Co-authored-by: Liam DeBeasi <liamdebeasi@icloud.com>

packages/vue/src/components/IonRouterOutlet.ts

@@ -15,6 +15,10 @@ import { IonRouterOutlet as IonRouterOutletCmp } from '@ionic/core/components/io
 import { matchedRouteKey, routeLocationKey, useRoute } from 'vue-router';
 import { fireLifecycle, generateId, getConfig, defineCustomElement } from '../utils';
 
+const isViewVisible = (enteringEl: HTMLElement) => {
+  return !enteringEl.classList.contains('ion-page-hidden') && !enteringEl.classList.contains('ion-page-invisible');
+}
+
 let viewDepthKey: InjectionKey<0> = Symbol(0);
 export const IonRouterOutlet = /*@__PURE__*/ defineComponent({
   name: 'IonRouterOutlet',
@@ -218,13 +222,35 @@ export const IonRouterOutlet = /*@__PURE__*/ defineComponent({
 
 See https://ionicframework.com/docs/vue/navigation#ionpage for more information.`);
       }
-
       if (enteringViewItem === leavingViewItem) return;
 
       if (!leavingViewItem && prevRouteLastPathname) {
         leavingViewItem = viewStacks.findViewItemByPathname(prevRouteLastPathname, id);
       }
 
+      /**
+       * If the entering view is already
+       * visible, then no transition is needed.
+       * This is most common when navigating
+       * from a tabs page to a non-tabs page
+       * and then back to the tabs page.
+       * Even when the tabs context navigated away,
+       * the inner tabs page was still active.
+       * This also avoids an issue where
+       * the previous tabs page is incorrectly
+       * unmounted since it would automatically
+       * unmount the previous view.
+       *
+       * This should also only apply to entering and
+       * leaving items in the same router outlet (i.e.
+       * Tab1 and Tab2), otherwise this will
+       * return early for swipe to go back when
+       * going from a non-tabs page to a tabs page.
+       */
+      if (isViewVisible(enteringEl) && leavingViewItem !== undefined && !isViewVisible(leavingViewItem.ionPageElement)) {
+        return;
+      }
+
       fireLifecycle(enteringViewItem.vueComponent, enteringViewItem.vueComponentRef, LIFECYCLE_WILL_ENTER);
 
       if (leavingViewItem && enteringViewItem !== leavingViewItem) {

packages/vue/test-app/tests/e2e/specs/tabs.js

@@ -290,7 +290,7 @@ describe('Tabs', () => {
     cy.url().should('include', '/tabs/tab1/child-one?key=value');
   });
 
-  // Verifies fix for https://github.com/ionic-team/ionic-framework/issues/23699
+  // Verifies fix for https://github.com/ionic-team/ionic-framework/issues/24353
   it('should handle clicking tab multiple times without query string', () => {
     cy.visit('http://localhost:8080/tabs/tab1');
 
@@ -312,6 +312,33 @@ describe('Tabs', () => {
     cy.ionPageVisible('tab2');
     cy.ionPageHidden('tab1');
   });
+
+  // Verifies fix for https://github.com/ionic-team/ionic-framework/issues/24332
+  it('should not unmount tab 1 when leaving tabs context', () => {
+    cy.visit('http://localhost:8080/tabs');
+    cy.ionPageVisible('tab1');
+
+    // Dynamically add tab 4 because tab 3 redirects to tab 1
+    cy.get('#add-tab').click();
+
+    cy.get('ion-tab-button#tab-button-tab4').click();
+    cy.ionPageHidden('tab1');
+    cy.ionPageVisible('tab4');
+
+    cy.get('ion-tab-button#tab-button-tab2').click();
+    cy.ionPageHidden('tab4');
+    cy.ionPageVisible('tab2');
+
+    cy.get('[data-pageid="tab2"] #routing').click();
+    cy.ionPageVisible('routing');
+    cy.ionPageHidden('tabs');
+
+    cy.ionBackClick('routing');
+    cy.ionPageDoesNotExist('routing');
+    cy.ionPageVisible('tabs');
+    cy.ionPageVisible('tab2');
+    cy.ionPageHidden('tab1');
+  });
 })
 
 describe('Tabs - Swipe to Go Back', () => {