feat(core/tree)- Improve keyboard activation for node selection and expand/collapse for tree-item

.changeset/keyboard-tree-item-a11y.md

@@ -0,0 +1,10 @@
+---
+"@siemens/ix": patch
+---
+
+fix(core/tree-item): improve keyboard accessibility for tree item interactions
+
+Tree item chevron and node container are now properly activatable via Enter and
+Space keys. Focus is preserved across tree refreshes. Added `aria-expanded` and
+`aria-disabled` attributes to interactive controls for correct screen-reader
+announcement.

packages/core/src/components/tree-item/tree-item.scss

@@ -10,6 +10,7 @@
 @use 'misc/common-variables' as vars;
 @use 'mixins/text-truncation';
 @use 'mixins/shadow-dom/component';
+@use 'mixins/shadow-dom/focus-visible';
 
 :host {
   display: flex;
@@ -28,9 +29,14 @@
     height: vars.$x-large-space;
     flex-grow: 1;
     align-items: center;
+    outline: none;
 
     @include text-truncation.ellipsis;
 
+    &:focus-visible {
+      @include focus-visible.ix-focus-visible;
+    }
+
     .tree-node-text {
       @include text-truncation.ellipsis;
     }
@@ -46,10 +52,15 @@
 
     ix-icon {
       transition: transform var(--theme-default-time) ease-in-out;
+      outline: none;
 
       &.icon-toggle-down {
         transform: rotate(90deg);
       }
+
+      &:focus-visible {
+        @include focus-visible.ix-focus-visible;
+      }
     }
   }
 }

packages/core/src/components/tree-item/tree-item.tsx

@@ -7,7 +7,15 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import { Component, Event, EventEmitter, h, Host, Prop } from '@stencil/core';
+import {
+  Component,
+  Element,
+  Event,
+  EventEmitter,
+  h,
+  Host,
+  Prop,
+} from '@stencil/core';
 import { TreeItemContext } from '../tree/tree-model';
 import { iconChevronRightSmall } from '@siemens/ix-icons/icons';
 
@@ -20,6 +28,8 @@
   shadow: true,
 })
 export class TreeItem {
+  @Element() hostElement!: HTMLIxTreeItemElement;
+
   /**
    * Text
    */
@@ -76,6 +86,16 @@
                 ['icon-toggle-down']: !!this.context?.isExpanded,
               }}
               color="color-std-text"
+              tabIndex={isDisabled ? -1 : 0}
+              role="button"
+              aria-expanded={!!this.context?.isExpanded}
+              aria-disabled={isDisabled ?? false}
+              aria-label={
+                this.ariaLabelChevronIcon ??
+                (this.context?.isExpanded
+                  ? 'Collapse tree item'
+                  : 'Expand tree item')
+              }
               onClick={(e: Event) => {
                 if (isDisabled) {
                   return;
@@ -84,24 +104,41 @@
                 e.stopPropagation();
                 this.toggle.emit();
               }}
-              aria-label={
-                this.ariaLabelChevronIcon ??
-                (this.context?.isExpanded
-                  ? 'Collapse tree item'
-                  : 'Expand tree item')
-              }
+              onKeyDown={(e: KeyboardEvent) => {
+                if (isDisabled) {
+                  return;
+                }
+                if (e.key === ' ' || e.key === 'Enter') {
+                  e.preventDefault();
+                  e.stopPropagation();
+                  this.toggle.emit();
+                }
+              }}
             />
           ) : null}
         </div>
         <div
           class="tree-node-container"
+          role="button"
+          tabIndex={isDisabled ? -1 : 0}
+          aria-disabled={isDisabled ?? false}
+          onKeyDown={(e: KeyboardEvent) => {
+            if (isDisabled) {
+              return;
+            }
+            if (e.key === ' ' || e.key === 'Enter') {
+              e.preventDefault();
+              e.stopPropagation();
+              (e.currentTarget as HTMLElement).click();
+            }
+          }}
           onClick={() => {
             if (isDisabled) {
               return;
             }
             this.itemClick.emit();
           }}
         >
           <div class="tree-node-text">{this.text}</div>
           <slot></slot>
         </div>

packages/core/src/components/tree/test/tree.ct.ts

@@ -92,6 +92,27 @@ const updateModel = async (tree: Locator, updatedModel: any) => {
   );
 };
 
+regressionTest.describe('accessibility', () => {
+  regressionTest('collapsed', async ({ mount, page, makeAxeBuilder }) => {
+    await initializeTree(mount, page);
+
+    const accessibilityScanResults = await makeAxeBuilder().analyze();
+    expect(accessibilityScanResults.violations).toEqual([]);
+  });
+
+  regressionTest('expanded', async ({ mount, page, makeAxeBuilder }) => {
+    const tree = await initializeTree(mount, page);
+
+    await tree
+      .locator('ix-tree-item', { hasText: 'Sample', hasNotText: 'Child' })
+      .locator('ix-icon')
+      .click();
+
+    const accessibilityScanResults = await makeAxeBuilder().analyze();
+    expect(accessibilityScanResults.violations).toEqual([]);
+  });
+});
+
 regressionTest('renders', async ({ mount, page }) => {
   const tree = await initializeTree(mount, page);
   const item = tree.locator('ix-tree-item').nth(0);
@@ -749,3 +770,161 @@ regressionTest(
     );
   }
 );
+
+regressionTest(
+  'should expand item when Enter is pressed on chevron',
+  async ({ mount, page }) => {
+    const tree = await initializeTree(mount, page);
+
+    const sampleItem = tree.locator('ix-tree-item', {
+      hasText: 'Sample',
+      hasNotText: 'Child',
+    });
+    const chevron = sampleItem.locator('ix-icon');
+
+    await chevron.focus();
+    await page.keyboard.press('Enter');
+
+    const children = tree.locator('ix-tree-item', {
+      hasText: 'Sample Child ',
+    });
+    await expect(children.nth(0)).toBeVisible();
+  }
+);
+
+regressionTest(
+  'should expand item when Space is pressed on chevron',
+  async ({ mount, page }) => {
+    const tree = await initializeTree(mount, page);
+
+    const sampleItem = tree.locator('ix-tree-item', {
+      hasText: 'Sample',
+      hasNotText: 'Child',
+    });
+    const chevron = sampleItem.locator('ix-icon');
+
+    await chevron.focus();
+    await page.keyboard.press('Space');
+
+    const children = tree.locator('ix-tree-item', {
+      hasText: 'Sample Child ',
+    });
+    await expect(children.nth(0)).toBeVisible();
+  }
+);
+
+regressionTest(
+  'should select item when Enter is pressed on tree-node-container',
+  async ({ mount, page }) => {
+    const tree = await initializeTree(mount, page);
+
+    const sampleItem = tree.locator('ix-tree-item', {
+      hasText: 'Sample',
+      hasNotText: 'Child',
+    });
+    const container = sampleItem.locator('.tree-node-container');
+
+    await container.focus();
+    await page.keyboard.press('Enter');
+
+    await expect(sampleItem).toHaveClass(/selected/);
+  }
+);
+
+regressionTest(
+  'should select item when Space is pressed on tree-node-container',
+  async ({ mount, page }) => {
+    const tree = await initializeTree(mount, page);
+
+    const sampleItem = tree.locator('ix-tree-item', {
+      hasText: 'Sample',
+      hasNotText: 'Child',
+    });
+    const container = sampleItem.locator('.tree-node-container');
+
+    await container.focus();
+    await page.keyboard.press('Space');
+
+    await expect(sampleItem).toHaveClass(/selected/);
+  }
+);
+
+regressionTest(
+  'disabled item should not respond to keyboard activation',
+  async ({ mount, page }) => {
+    await mount(`
+      <div style="height: 20rem; width: 100%;">
+        <ix-tree root="root"></ix-tree>
+      </div>
+    `);
+
+    const tree = page.locator('ix-tree');
+    await tree.evaluate(
+      (element: HTMLIxTreeElement, args) => {
+        element.model = args.model;
+        element.context = args.context;
+      },
+      {
+        model: {
+          root: {
+            id: 'root',
+            data: { name: '' },
+            hasChildren: true,
+            children: ['parent'],
+          },
+          parent: {
+            id: 'parent',
+            data: { name: 'Disabled Parent' },
+            hasChildren: true,
+            children: ['child'],
+            disabled: true,
+          },
+          child: {
+            id: 'child',
+            data: { name: 'Child' },
+            hasChildren: false,
+            children: [],
+          },
+        } as TreeModel<unknown>,
+        context: {
+          root: { isExpanded: true, isSelected: false },
+          parent: { isExpanded: false, isSelected: false },
+          child: { isExpanded: false, isSelected: false },
+        } as TreeContext,
+      }
+    );
+
+    await expect(tree).toHaveClass(/hydrated/);
+
+    const parent = tree.locator('ix-tree-item', { hasText: 'Disabled Parent' });
+    const container = parent.locator('.tree-node-container');
+
+    await container.focus();
+    await page.keyboard.press('Enter');
+
+    await expect(parent).not.toHaveClass(/selected/);
+    await expect(
+      tree.locator('ix-tree-item', { hasText: 'Child' })
+    ).not.toBeVisible();
+  }
+);
+
+regressionTest(
+  'should preserve focus on tree-node-container after refreshTree',
+  async ({ mount, page }) => {
+    const tree = await initializeTree(mount, page);
+
+    const sampleItem = tree.locator('ix-tree-item', {
+      hasText: 'Sample',
+      hasNotText: 'Child',
+    });
+    const container = sampleItem.locator('.tree-node-container');
+
+    await container.focus();
+    await expect(container).toBeFocused();
+
+    await tree.evaluate((el: HTMLIxTreeElement) => el.refreshTree());
+
+    await expect(container).toBeFocused();
+  }
+);

packages/core/src/components/tree/tree.tsx

@@ -314,17 +314,69 @@ export class Tree {
     );
   }
 
+  private getFocusedTreeNodeInfo(): {
+    nodeId: string;
+    target: 'chevron' | 'item';
+  } | null {
+    const activeEl = document.activeElement;
+    if (!(activeEl instanceof HTMLElement)) {
+      return null;
+    }
+
+    const nodeId = this.getTreeNodeId(activeEl);
+    if (!nodeId) {
+      return null;
+    }
+
+    const shadowActive = activeEl.shadowRoot?.activeElement;
+    if (shadowActive?.tagName === 'IX-ICON') {
+      return { nodeId, target: 'chevron' };
+    }
+
+    if (
+      shadowActive instanceof HTMLElement &&
+      shadowActive.classList.contains('tree-node-container')
+    ) {
+      return { nodeId, target: 'item' };
+    }
+
+    return null;
+  }
+
   /**
    * Refresh the list.
    * This will re-render the list with the current model and context.
    */
   @Method()
   async refreshTree(options: RefreshTreeOptions = defaultRefreshTreeOptions) {
     if (this.hyperlist) {
+      const focusInfo = this.getFocusedTreeNodeInfo();
+
       this.hyperlist.refresh(
         this.hostElement,
         this.getVirtualizerOptions(options)
       );
+
+      if (focusInfo) {
+        const treeItem = this.hostElement.querySelector<HTMLElement>(
+          `[data-tree-node-id="${CSS.escape(focusInfo.nodeId)}"]`
+        );
+        if (focusInfo.target === 'chevron') {
+          const chevron =
+            treeItem?.shadowRoot?.querySelector<HTMLElement>('ix-icon');
+          if (chevron) {
+            chevron.focus();
+          } else {
+            treeItem?.shadowRoot
+              ?.querySelector<HTMLElement>('.tree-node-container')
+              ?.focus();
+          }
+        } else {
+          treeItem?.shadowRoot
+            ?.querySelector<HTMLElement>('.tree-node-container')
+            ?.focus();
+        }
+      }
     }
   }