fix(vue): tab bar now works with slot="top" (#22461)

resolves #22456

packages/vue/src/components/IonTabBar.ts

@@ -27,7 +27,8 @@ export const IonTabBar = defineComponent({
      * to a tab from another tab, we can correctly
      * show any child pages if necessary.
      */
-    (currentInstance.subTree.children as VNode[]).forEach((child: VNode) => {
+    const children = (currentInstance.subTree.children || []) as VNode[];
+    children.forEach((child: VNode) => {
       if (child.type && (child.type as any).name === 'IonTabButton') {
         tabState.tabs[child.props.tab] = {
           originalHref: child.props.href,
@@ -45,7 +46,7 @@ export const IonTabBar = defineComponent({
     });
 
     const checkActiveTab = (currentRoute: any) => {
-      const childNodes = currentInstance.subTree.children as VNode[];
+      const childNodes = (currentInstance.subTree.children || []) as VNode[];
       const { tabs, activeTab: prevActiveTab } = tabState;
       const tabKeys = Object.keys(tabs);
       const activeTab = tabKeys

packages/vue/src/components/IonTabs.ts

@@ -1,10 +1,50 @@
-import { h, defineComponent } from 'vue';
+import { h, defineComponent, VNode } from 'vue';
 import { IonRouterOutlet } from './IonRouterOutlet';
 
 export const IonTabs = defineComponent({
   name: 'IonTabs',
   render() {
     const { $slots: slots } = this;
+    const slottedContent = slots.default && slots.default();
+    let childrenToRender = [
+      h('div', {
+        class: 'tabs-inner',
+        style: {
+            'position': 'relative',
+            'flex': '1',
+            'contain': 'layout size style'
+        }
+      }, [
+        h(IonRouterOutlet, { tabs: true })
+      ])
+    ];
+
+    /**
+     * If ion-tab-bar has slot="top" it needs to be
+     * rendered before `.tabs-inner` otherwise it will
+     * not show above the tab content.
+     */
+    if (slottedContent && slottedContent.length > 0) {
+      const topSlottedTabBar = slottedContent.find((child: VNode) => {
+        const isTabBar = child.type && (child.type as any).name === 'IonTabBar';
+        const hasTopSlot = child.props?.slot === 'top';
+
+        return isTabBar && hasTopSlot;
+      });
+
+      if (topSlottedTabBar) {
+        childrenToRender = [
+          ...slottedContent,
+          ...childrenToRender
+        ];
+      } else {
+        childrenToRender = [
+          ...childrenToRender,
+          ...slottedContent
+        ]
+      }
+    }
+
     return h(
       'ion-tabs',
       {
@@ -22,23 +62,7 @@ export const IonTabs = defineComponent({
           'z-index': '0'
         }
       },
-      [
-        h(
-          'div',
-          {
-            class: 'tabs-inner',
-            style: {
-              'position': 'relative',
-              'flex': '1',
-              'contain': 'layout size style'
-            }
-          },
-          [
-            h(IonRouterOutlet, { tabs: true })
-          ]
-        ),
-        ...slots.default && slots.default()
-      ]
+      childrenToRender
     )
   }
 });

packages/vue/test-app/src/views/TabsSecondary.vue

@@ -2,7 +2,7 @@
   <ion-page data-pageid="tabs-secondary">
     <ion-content>
       <ion-tabs id="tabs">
-        <ion-tab-bar slot="bottom">
+        <ion-tab-bar slot="top">
           <ion-tab-button tab="tab1-secondary" href="/tabs-secondary/tab1">
             <ion-icon :icon="triangle" />
             <ion-label>Tab 1</ion-label>

packages/vue/test-app/tests/unit/tab-bar.spec.ts

@@ -0,0 +1,105 @@
+import { mount } from '@vue/test-utils';
+import { createRouter, createWebHistory } from '@ionic/vue-router';
+import { IonicVue, IonApp, IonRouterOutlet, IonPage, IonTabs, IonTabBar } from '@ionic/vue';
+
+const App = {
+  components: { IonApp, IonRouterOutlet },
+  template: '<ion-app><ion-router-outlet /></ion-app>',
+}
+
+describe('ion-tab-bar', () => {
+  it('should render in the top slot', async () => {
+    const Tabs = {
+      components: { IonPage, IonTabs, IonTabBar },
+      template: `
+        <ion-page>
+          <ion-tabs>
+            <ion-tab-bar slot="top"></ion-tab-bar>
+          </ion-tabs>
+        </ion-page>
+      `,
+    }
+
+    const router = createRouter({
+      history: createWebHistory(process.env.BASE_URL),
+      routes: [
+        { path: '/', component: Tabs }
+      ]
+    });
+
+    router.push('/');
+    await router.isReady();
+    const wrapper = mount(App, {
+      global: {
+        plugins: [router, IonicVue]
+      }
+    });
+
+    const innerHTML = wrapper.find('ion-tabs').html();
+    expect(innerHTML).toContain(`<ion-tab-bar slot="top"></ion-tab-bar><div class="tabs-inner" style="position: relative; flex: 1; contain: layout size style;">`);
+
+  });
+
+  it('should render in the bottom slot', async () => {
+    const Tabs = {
+      components: { IonPage, IonTabs, IonTabBar },
+      template: `
+        <ion-page>
+          <ion-tabs>
+            <ion-tab-bar slot="bottom"></ion-tab-bar>
+          </ion-tabs>
+        </ion-page>
+      `,
+    }
+
+    const router = createRouter({
+      history: createWebHistory(process.env.BASE_URL),
+      routes: [
+        { path: '/', component: Tabs }
+      ]
+    });
+
+    router.push('/');
+    await router.isReady();
+    const wrapper = mount(App, {
+      global: {
+        plugins: [router, IonicVue]
+      }
+    });
+
+    const innerHTML = wrapper.find('ion-tabs').html();
+    expect(innerHTML).toContain(`<div class="tabs-inner" style="position: relative; flex: 1; contain: layout size style;"><ion-router-outlet tabs="true"></ion-router-outlet></div><ion-tab-bar slot="bottom"></ion-tab-bar>`);
+
+  });
+
+  it('should render in the default slot', async () => {
+    const Tabs = {
+      components: { IonPage, IonTabs, IonTabBar },
+      template: `
+        <ion-page>
+          <ion-tabs>
+            <ion-tab-bar></ion-tab-bar>
+          </ion-tabs>
+        </ion-page>
+      `,
+    }
+
+    const router = createRouter({
+      history: createWebHistory(process.env.BASE_URL),
+      routes: [
+        { path: '/', component: Tabs }
+      ]
+    });
+
+    router.push('/');
+    await router.isReady();
+    const wrapper = mount(App, {
+      global: {
+        plugins: [router, IonicVue]
+      }
+    });
+
+    const innerHTML = wrapper.find('ion-tabs').html();
+    expect(innerHTML).toContain(`<div class="tabs-inner" style="position: relative; flex: 1; contain: layout size style;"><ion-router-outlet tabs="true"></ion-router-outlet></div><ion-tab-bar></ion-tab-bar></ion-tabs>`)
+  });
+});