feat(tabs): add tabs property to retrieve tab elements

PiperOrigin-RevId: 563784477

tabs/harness.ts

@@ -53,9 +53,8 @@ export class TabsHarness extends Harness<Tabs> {
   get harnessedItems() {
     // Test access to protected property
     // tslint:disable-next-line:no-dict-access-on-struct-type
-    return (this.element['items'] as Array<ElementWithHarness<Tab>>)
+    return (this.element.tabs as Array<ElementWithHarness<Tab>>).map(item => {
-        .map(item => {
+      return (item.harness ?? new TabHarness(item)) as TabHarness;
-          return (item.harness ?? new TabHarness(item)) as TabHarness;
+    });
-        });
   }
 }

tabs/internal/tabs.ts

@@ -47,6 +47,13 @@ export class Tabs extends LitElement {
     setupHostAria(Tabs, {focusable: false});
   }
 
+  /**
+   * The tabs of this tab bar.
+   */
+  get tabs() {
+    return this.maybeTabItems.filter(isTab);
+  }
+
   /**
    * Index of the selected item.
    */
@@ -63,9 +70,6 @@ export class Tabs extends LitElement {
 
   @queryAssignedElements({flatten: true})
   private readonly maybeTabItems!: HTMLElement[];
-  private get items(): Tab[] {
-    return this.maybeTabItems.filter(isTab);
-  }
 
   // this tracks if items have changed, which triggers rendering so they can
   // be kept in sync
@@ -75,21 +79,21 @@ export class Tabs extends LitElement {
    * The item currently selected.
    */
   get selectedItem() {
-    return this.items[this.selected];
+    return this.tabs[this.selected];
   }
 
   /**
    * The item previously selected.
    */
   get previousSelectedItem() {
-    return this.items[this.previousSelected];
+    return this.tabs[this.previousSelected];
   }
 
   /**
    * The item currently focused.
    */
   private get focusedItem() {
-    return this.items.find((el: HTMLElement) => el.matches(':focus-within'));
+    return this.tabs.find((el: HTMLElement) => el.matches(':focus-within'));
   }
 
   private readonly internals = polyfillElementInternalsAria(
@@ -116,19 +120,19 @@ export class Tabs extends LitElement {
     }
     let indexToFocus = -1;
     const focused = this.focusedItem ?? this.selectedItem;
-    const itemCount = this.items.length;
+    const itemCount = this.tabs.length;
     const isPrevKey = key === 'ArrowLeft' || key === 'ArrowUp';
     if (key === 'Home') {
       indexToFocus = 0;
     } else if (key === 'End') {
       indexToFocus = itemCount - 1;
     } else {
-      const focusedIndex = this.items.indexOf(focused) || 0;
+      const focusedIndex = this.tabs.indexOf(focused) || 0;
       indexToFocus = focusedIndex + (isPrevKey ? -1 : 1);
       indexToFocus =
           indexToFocus < 0 ? itemCount - 1 : indexToFocus % itemCount;
     }
-    const itemToFocus = this.items[indexToFocus];
+    const itemToFocus = this.tabs[indexToFocus];
     if (itemToFocus !== null && itemToFocus !== focused) {
       this.updateFocusableItem(itemToFocus);
       itemToFocus.focus();
@@ -150,7 +154,7 @@ export class Tabs extends LitElement {
     const nowFocused =
         (this.getRootNode() as unknown as DocumentOrShadowRoot).activeElement as
         Tab;
-    if (this.items.indexOf(nowFocused) === -1) {
+    if (this.tabs.indexOf(nowFocused) === -1) {
       this.updateFocusableItem(this.selectedItem);
     }
   };
@@ -209,7 +213,7 @@ export class Tabs extends LitElement {
     const itemsChanged = changed.has('itemsDirty');
     // sync state with items.
     if (itemsChanged) {
-      this.items.forEach((item, i) => {
+      this.tabs.forEach((item, i) => {
         item.active = this.selected === i;
       });
     }
@@ -227,7 +231,7 @@ export class Tabs extends LitElement {
   }
 
   private updateFocusableItem(focusableItem: HTMLElement|null) {
-    for (const item of this.items) {
+    for (const item of this.tabs) {
       item.tabIndex = item === focusableItem ? 0 : -1;
     }
   }
@@ -248,7 +252,7 @@ export class Tabs extends LitElement {
       return;
     }
     const item = (target as Element).closest(`${this.localName} > *`) as Tab;
-    const i = this.items.indexOf(item);
+    const i = this.tabs.indexOf(item);
     if (i > -1 && this.selected !== i) {
       this.selected = i;
       this.updateFocusableItem(this.selectedItem);
@@ -264,7 +268,7 @@ export class Tabs extends LitElement {
   }
 
   private async itemsUpdateComplete() {
-    for (const item of this.items) {
+    for (const item of this.tabs) {
       await item.updateComplete;
     }
     return true;