fix: restore focus on toast dismiss

Author: mikeharv

packages/blockly/core/focus_manager.ts

@@ -302,6 +302,14 @@ export class FocusManager {
     return this.focusedNode;
   }
 
+  /**
+   * Returns the IFocusableNode that held focus immediately before the current
+   * focused node, or null if there is no such node.
+   */
+  getPreviouslyFocusedNode(): IFocusableNode | null {
+    return this.previouslyFocusedNode;
+  }
+
   /**
    * Focuses the specific IFocusableTree. This either means restoring active
    * focus to the tree's passively focused node, or focusing the tree's root

packages/blockly/core/toast.ts

@@ -5,6 +5,7 @@
  */
 
 import * as Css from './css.js';
+import {getFocusManager} from './focus_manager.js';
 import {Msg} from './msg.js';
 import * as aria from './utils/aria.js';
 import * as dom from './utils/dom.js';
@@ -139,8 +140,17 @@ export class Toast {
       closeIcon,
     );
     closeButton.addEventListener('click', () => {
+      const focusManager = getFocusManager();
+      const nodeToRestore = focusManager.getPreviouslyFocusedNode();
       toast.remove();
-      workspace.markFocused();
+      if (nodeToRestore?.canBeFocused()) {
+        focusManager.focusNode(nodeToRestore);
+      } else {
+        // No prior focus (e.g. a toast closed with the mouse before any
+        // Blockly node was focused). Park focus back on the workspace
+        // via FocusManager instead of dropping it on the document body.
+        focusManager.focusTree(workspace);
+      }
     });
 
     let timeout: ReturnType<typeof setTimeout>;

packages/blockly/tests/mocha/focus_manager_test.js

@@ -418,6 +418,25 @@ suite('FocusManager', function () {
     });
   });
 
+  suite('getPreviouslyFocusedNode()', function () {
+    test('by default returns null', function () {
+      assert.isNull(this.focusManager.getPreviouslyFocusedNode());
+    });
+
+    test('after losing focus to untracked element returns prior node', function () {
+      this.focusManager.registerTree(this.testFocusableTree1);
+      this.focusManager.focusNode(this.testFocusableTree1Node1);
+
+      document.body.focus();
+
+      assert.isNull(this.focusManager.getFocusedNode());
+      assert.strictEqual(
+        this.focusManager.getPreviouslyFocusedNode(),
+        this.testFocusableTree1Node1,
+      );
+    });
+  });
+
   suite('focusTree()', function () {
     test('for not registered tree throws', function () {
       const errorMsgRegex = /Attempted to focus unregistered tree.+?/;

packages/blockly/tests/mocha/toast_test.js

@@ -139,4 +139,37 @@ suite('Toasts', function () {
     assert.isNull(toast.getAttribute('aria-live'));
     assert.notEqual(toast.getAttribute('role'), Blockly.utils.aria.Role.STATUS);
   });
+
+  suite('dismiss focus', function () {
+    function closeToast(workspace) {
+      const closeButton = workspace
+        .getInjectionDiv()
+        .querySelector('.blocklyToastCloseButton');
+      closeButton.focus();
+      closeButton.click();
+    }
+
+    test('restores previously focused node on click', function () {
+      const block = this.workspace.newBlock('text_print');
+      block.initSvg();
+      block.render();
+      Blockly.getFocusManager().focusNode(block);
+      Blockly.Toast.show(this.workspace, {message: 'texas toast'});
+
+      closeToast(this.workspace);
+      assert.isFalse(this.toastIsVisible('texas toast'));
+      assert.strictEqual(Blockly.getFocusManager().getFocusedNode(), block);
+    });
+
+    test('falls back to workspace focus when nothing was previously focused', function () {
+      Blockly.Toast.show(this.workspace, {message: 'texas toast'});
+
+      closeToast(this.workspace);
+      assert.isFalse(this.toastIsVisible('texas toast'));
+      assert.strictEqual(
+        Blockly.getFocusManager().getFocusedNode(),
+        this.workspace.getWorkspaceFocusTarget(),
+      );
+    });
+  });
 });