fix(switch): pressing enter toggles the switch

PiperOrigin-RevId: 638508692

Author: asyncLiz

switch/internal/switch.ts

@@ -12,6 +12,10 @@ import {property, query} from 'lit/decorators.js';
 import {ClassInfo, classMap} from 'lit/directives/class-map.js';
 
 import {requestUpdateOnAriaChange} from '../../internal/aria/delegate.js';
+import {
+  afterDispatch,
+  setupDispatchHooks,
+} from '../../internal/events/dispatch-hooks.js';
 import {
   dispatchActivationClick,
   isActivationClick,
@@ -88,15 +92,33 @@ export class Switch extends switchBaseClass {
 
   constructor() {
     super();
-    if (!isServer) {
-      this.addEventListener('click', (event: MouseEvent) => {
-        if (!isActivationClick(event) || !this.input) {
+    if (isServer) {
+      return;
+    }
+
+    // This click listener does not currently need dispatch hooks since it does
+    // not check `event.defaultPrevented`.
+    this.addEventListener('click', (event: MouseEvent) => {
+      if (!isActivationClick(event) || !this.input) {
+        return;
+      }
+      this.focus();
+      dispatchActivationClick(this.input);
+    });
+
+    // Add the aria keyboard interaction pattern for switch and the Enter key.
+    // See https://www.w3.org/WAI/ARIA/apg/patterns/switch/.
+    setupDispatchHooks(this, 'keydown');
+    this.addEventListener('keydown', (event: KeyboardEvent) => {
+      afterDispatch(event, () => {
+        const ignoreEvent = event.defaultPrevented || event.key !== 'Enter';
+        if (ignoreEvent || this.disabled || !this.input) {
           return;
         }
-        this.focus();
-        dispatchActivationClick(this.input);
+
+        this.input.click();
       });
-    }
+    });
   }
 
   protected override render(): TemplateResult {

switch/switch_test.ts

@@ -8,12 +8,16 @@
 
 import {html} from 'lit';
 
+import {Environment} from '../testing/environment.js';
 import {createFormTests} from '../testing/forms.js';
 import {createTokenTests} from '../testing/tokens.js';
 
+import {SwitchHarness} from './harness.js';
 import {MdSwitch} from './switch.js';
 
 describe('<md-switch>', () => {
+  const env = new Environment();
+
   describe('.styles', () => {
     createTokenTests(MdSwitch.styles);
   });
@@ -117,4 +121,73 @@ describe('<md-switch>', () => {
       ],
     });
   });
+
+  describe('enter key activation', () => {
+    // Don't use harness.clickWithKeyboard() since it simulates a click event.
+    // The underlying `<input type="checkbox">` will not dispatch click events
+    // in response to the Enter key.
+
+    it('should toggle the switch on', async () => {
+      // Arrange
+      const root = env.render(html`<md-switch></md-switch>`);
+      const harness = new SwitchHarness(root.querySelector('md-switch')!);
+
+      // Act
+      await harness.keypress('Enter');
+      await harness.element.updateComplete;
+
+      // Assert
+      expect(harness.element.selected)
+        .withContext('switch is selected after Enter')
+        .toBeTrue();
+    });
+
+    it('should toggle the switch off', async () => {
+      // Arrange
+      const root = env.render(html`<md-switch selected></md-switch>`);
+      const harness = new SwitchHarness(root.querySelector('md-switch')!);
+
+      // Act
+      await harness.keypress('Enter');
+      await harness.element.updateComplete;
+
+      // Assert
+      expect(harness.element.selected)
+        .withContext('switch is unselected after Enter')
+        .toBeFalse();
+    });
+
+    it('should not toggle the switch when disabled', async () => {
+      // Arrange
+      const root = env.render(html`<md-switch disabled></md-switch>`);
+      const harness = new SwitchHarness(root.querySelector('md-switch')!);
+
+      // Act
+      await harness.keypress('Enter');
+      await harness.element.updateComplete;
+
+      // Assert
+      expect(harness.element.selected)
+        .withContext('disabled switch is not selected after Enter')
+        .toBeFalse();
+    });
+
+    it('should not toggle the switch when keydown event is canceled', async () => {
+      // Arrange
+      const root = env.render(html`<md-switch></md-switch>`);
+      const harness = new SwitchHarness(root.querySelector('md-switch')!);
+      harness.element.addEventListener('keydown', (event) => {
+        event.preventDefault();
+      });
+
+      // Act
+      await harness.keypress('Enter');
+      await harness.element.updateComplete;
+
+      // Assert
+      expect(harness.element.selected)
+        .withContext('switch is not selected when Enter is canceled')
+        .toBeFalse();
+    });
+  });
 });