Merge pull request #85 from github/add-activetab-selectedtabindex-props

add activeTab, selectedTabIndex props

Author: owenniblock

src/tab-container-element.ts

@@ -111,6 +111,10 @@ export class TabContainerElement extends HTMLElement {
     )
   }
 
+  get activeTab() {
+    return this.#tabs[this.selectedTabIndex]
+  }
+
   get activePanel() {
     return this.#panelSlot.assignedNodes()[0] as HTMLElement
   }
@@ -189,7 +193,7 @@ export class TabContainerElement extends HTMLElement {
     const tabs = this.#tabs
     if (!tabs.includes(tab as HTMLElement)) return
 
-    const currentIndex = tabs.indexOf(tabs.find(e => e.matches('[aria-selected="true"]'))!)
+    const currentIndex = this.selectedTabIndex
     const vertical = tab.closest('[role="tablist"]')?.getAttribute('aria-orientation') === 'vertical'
     const prevTab = event.code === 'ArrowLeft' || (vertical && event.code === 'ArrowUp')
     const nextTab = event.code === 'ArrowRight' || (vertical && event.code === 'ArrowDown')
@@ -226,6 +230,14 @@ export class TabContainerElement extends HTMLElement {
     }
   }
 
+  get selectedTabIndex(): number {
+    return this.#tabs.findIndex(el => el.matches('[aria-selected=true]'))
+  }
+
+  set selectedTabIndex(i: number) {
+    this.selectTab(i)
+  }
+
   selectTab(index: number): void {
     if (!this.#setupComplete) {
       const tabListSlot = this.#tabListSlot
@@ -283,7 +295,7 @@ export class TabContainerElement extends HTMLElement {
         for (const el of afterSlotted) el.setAttribute('slot', 'after-panels')
       }
       const defaultTab = Number(this.getAttribute('default-tab') || -1)
-      const defaultIndex = defaultTab >= 0 ? defaultTab : this.#tabs.findIndex(el => el.matches('[aria-selected=true]'))
+      const defaultIndex = defaultTab >= 0 ? defaultTab : this.selectedTabIndex
       index = index >= 0 ? index : Math.max(0, defaultIndex)
     }
 

test/test.js

@@ -183,6 +183,8 @@ describe('tab-container', function () {
         'change events point to second panel',
       )
       assert.equal(document.activeElement, tabs[1])
+      assert.equal(tabContainer.activeTab, tabs[1])
+      assert.equal(tabContainer.selectedTabIndex, 1)
     })
 
     it('keyboard shortcuts work and `tab-container-changed` events are dispatched', function () {
@@ -208,6 +210,8 @@ describe('tab-container', function () {
       assert.deepStrictEqual(tabs.map(isSelected), [true, false, false], 'First tab is selected')
       assert.deepStrictEqual(panels.map(isHidden), [false, true, true], 'First panel is visible')
       assert.equal(document.activeElement, tabs[0])
+      assert.equal(tabContainer.activeTab, tabs[0])
+      assert.equal(tabContainer.selectedTabIndex, 0)
       assert.equal(events.length, 2, 'tab-container-change(d) called')
       assert.deepStrictEqual(
         events.map(e => e.type),
@@ -301,6 +305,8 @@ describe('tab-container', function () {
         'change events point to second panel',
       )
       assert.equal(document.activeElement, tabs[1])
+      assert.equal(tabContainer.activeTab, tabs[1])
+      assert.equal(tabContainer.selectedTabIndex, 1)
     })
 
     it('result in noop, when selectTab receives out of bounds index', function () {
@@ -445,6 +451,8 @@ describe('tab-container', function () {
       assert.deepStrictEqual(tabs.map(isSelected), [false, false, true], 'Third tab is selected')
       assert.deepStrictEqual(panels.map(isHidden), [true, true, false], 'Third panel is visible')
       assert.equal(document.activeElement, tabs[2])
+      assert.equal(tabContainer.activeTab, tabs[2])
+      assert.equal(tabContainer.selectedTabIndex, 2)
       assert.equal(events.length, 2, 'tab-container-change(d) called')
       assert.deepStrictEqual(
         events.map(e => e.type),
@@ -467,6 +475,8 @@ describe('tab-container', function () {
       assert.deepStrictEqual(tabs.map(isSelected), [true, false, false], 'First tab is selected')
       assert.deepStrictEqual(panels.map(isHidden), [false, true, true], 'First panel is visible')
       assert.equal(document.activeElement, tabs[0])
+      assert.equal(tabContainer.activeTab, tabs[0])
+      assert.equal(tabContainer.selectedTabIndex, 0)
       assert.equal(events.length, 2, 'tab-container-change(d) called')
       assert.deepStrictEqual(
         events.map(e => e.type),
@@ -489,6 +499,8 @@ describe('tab-container', function () {
       assert.deepStrictEqual(tabs.map(isSelected), [false, true, false], 'Second tab is selected')
       assert.deepStrictEqual(panels.map(isHidden), [true, false, true], 'Second panel is visible')
       assert.equal(document.activeElement, tabs[1])
+      assert.equal(tabContainer.activeTab, tabs[1])
+      assert.equal(tabContainer.selectedTabIndex, 1)
       assert.equal(events.length, 2, 'tab-container-change(d) called')
       assert.deepStrictEqual(
         events.map(e => e.type),
@@ -511,6 +523,8 @@ describe('tab-container', function () {
       assert.deepStrictEqual(tabs.map(isSelected), [false, false, true], 'Third tab is selected')
       assert.deepStrictEqual(panels.map(isHidden), [true, true, false], 'Third panel is visible')
       assert.equal(document.activeElement, tabs[2])
+      assert.equal(tabContainer.activeTab, tabs[2])
+      assert.equal(tabContainer.selectedTabIndex, 2)
       assert.equal(events.length, 2, 'tab-container-change(d) called')
       assert.deepStrictEqual(
         events.map(e => e.type),
@@ -534,6 +548,8 @@ describe('tab-container', function () {
       assert.deepStrictEqual(tabs.map(isSelected), [false, false, true], 'Third tab is selected')
       assert.deepStrictEqual(panels.map(isHidden), [true, true, false], 'Third panel is visible')
       assert.equal(document.activeElement, tabs[2])
+      assert.equal(tabContainer.activeTab, tabs[2])
+      assert.equal(tabContainer.selectedTabIndex, 2)
       assert.equal(events.length, 2, 'tab-container-change(d) called')
       assert.deepStrictEqual(
         events.map(e => e.type),
@@ -556,6 +572,8 @@ describe('tab-container', function () {
       assert.deepStrictEqual(tabs.map(isSelected), [true, false, false], 'First tab is selected')
       assert.deepStrictEqual(panels.map(isHidden), [false, true, true], 'First panel is visible')
       assert.equal(document.activeElement, tabs[0])
+      assert.equal(tabContainer.activeTab, tabs[0])
+      assert.equal(tabContainer.selectedTabIndex, 0)
       assert.equal(events.length, 2, 'tab-container-change(d) called')
       assert.deepStrictEqual(
         events.map(e => e.type),
@@ -578,6 +596,8 @@ describe('tab-container', function () {
       assert.deepStrictEqual(tabs.map(isSelected), [false, true, false], 'Second tab is selected')
       assert.deepStrictEqual(panels.map(isHidden), [true, false, true], 'Second panel is visible')
       assert.equal(document.activeElement, tabs[1])
+      assert.equal(tabContainer.activeTab, tabs[1])
+      assert.equal(tabContainer.selectedTabIndex, 1)
       assert.equal(events.length, 2, 'tab-container-change(d) called')
       assert.deepStrictEqual(
         events.map(e => e.type),
@@ -600,6 +620,8 @@ describe('tab-container', function () {
       assert.deepStrictEqual(tabs.map(isSelected), [false, false, true], 'Third tab is selected')
       assert.deepStrictEqual(panels.map(isHidden), [true, true, false], 'Third panel is visible')
       assert.equal(document.activeElement, tabs[2])
+      assert.equal(tabContainer.activeTab, tabs[2])
+      assert.equal(tabContainer.selectedTabIndex, 2)
       assert.equal(events.length, 2, 'tab-container-change(d) called')
       assert.deepStrictEqual(
         events.map(e => e.type),