fix: fix pinch to zoom

core/touch.ts

@@ -158,20 +158,20 @@ export function shouldHandleEvent(e: Event|PseudoEvent): boolean {
  * Get the touch identifier from the given event.  If it was a mouse event, the
  * identifier is the string 'mouse'.
  *
- * @param e Mouse event or touch event.
- * @returns The touch identifier from the first changed touch, if defined.
- *     Otherwise 'mouse'.
+ * @param e Pointer event, mouse event, or touch event.
+ * @returns The pointerId, or touch identifier from the first changed touch, if
+ *     defined. Otherwise 'mouse'.
  * @alias Blockly.Touch.getTouchIdentifierFromEvent
  */
 export function getTouchIdentifierFromEvent(e: Event|PseudoEvent): string {
-  if (e instanceof MouseEvent) {
-    return 'mouse';
-  }
-
   if (e instanceof PointerEvent) {
     return String(e.pointerId);
   }
 
+  if (e instanceof MouseEvent) {
+    return 'mouse';
+  }
+
   /**
    * TODO(#6097): Fix types. This is a catch-all for everything but mouse
    * and pointer events.

tests/mocha/index.html

@@ -97,6 +97,7 @@
           'Blockly.test.registry',
           'Blockly.test.serialization',
           'Blockly.test.shortcutRegistry',
+          'Blockly.test.touch',
           'Blockly.test.theme',
           'Blockly.test.toolbox',
           'Blockly.test.tooltip',

tests/mocha/touch_test.js

@@ -0,0 +1,95 @@
+/**
+ * @license
+ * Copyright 2022 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+ goog.declareModuleId('Blockly.test.touch');
+
+ import {sharedTestSetup, sharedTestTeardown} from './test_helpers/setup_teardown.js';
+
+ suite('Touch', function() {
+    setup(function() {
+        sharedTestSetup.call(this);
+    });
+
+    teardown(function() {
+        Blockly.Touch.clearTouchIdentifier();
+        sharedTestTeardown.call(this);
+    });
+
+    suite('shouldHandleTouch', function() {
+        test('handles mousedown event', function() {
+            const mouseEvent = new MouseEvent('mousedown');
+            chai.assert.isTrue(Blockly.Touch.shouldHandleEvent(mouseEvent));
+        });
+
+        test('handles multiple mousedown events', function() {
+            const mouseEvent1 = new MouseEvent('mousedown');
+            const mouseEvent2 = new MouseEvent('mousedown');
+            Blockly.Touch.shouldHandleEvent(mouseEvent1);
+            chai.assert.isTrue(Blockly.Touch.shouldHandleEvent(mouseEvent2));
+        });
+
+        test('does not handle mouseup if not tracking touch', function() {
+            const mouseEvent = new MouseEvent('mouseup');
+            chai.assert.isFalse(Blockly.Touch.shouldHandleEvent(mouseEvent));
+        });
+
+        test('handles mouseup if already tracking a touch', function() {
+            const mousedown = new MouseEvent('mousedown');
+            const mouseup = new MouseEvent('mouseup');
+            // Register the mousedown event first
+            Blockly.Touch.shouldHandleEvent(mousedown);
+            chai.assert.isTrue(Blockly.Touch.shouldHandleEvent(mouseup));
+        });
+
+        test('handles pointerdown if this is a new touch', function() {
+            const pointerdown = new PointerEvent('pointerdown', {pointerId: 1, pointerType: 'touch'});
+            chai.assert.isTrue(Blockly.Touch.shouldHandleEvent(pointerdown));
+        });
+
+        test('does not handle pointerdown if part of a different touch', function() {
+            const pointerdown1 = new PointerEvent('pointerdown', {pointerId: 1, pointerType: 'touch'});
+            const pointerdown2 = new PointerEvent('pointerdown', {pointerId: 2, pointerType: 'touch'});
+            Blockly.Touch.shouldHandleEvent(pointerdown1);
+            chai.assert.isFalse(Blockly.Touch.shouldHandleEvent(pointerdown2));
+        });
+
+        test('does not handle pointerdown after a mousedown', function() {
+            const mouseEvent = new MouseEvent('mousedown');
+            const pointerdown = new PointerEvent('pointerdown', {pointerId: 1, pointerType: 'touch'});
+            Blockly.Touch.shouldHandleEvent(mouseEvent);
+            chai.assert.isFalse(Blockly.Touch.shouldHandleEvent(pointerdown));
+        });
+
+        test('does not handle pointerup if not tracking touch', function() {
+            const pointerup = new PointerEvent('pointerup', {pointerId: 1, pointerType: 'touch'});
+            chai.assert.isFalse(Blockly.Touch.shouldHandleEvent(pointerup));
+        });
+
+        test('handles pointerup if part of existing touch', function() {
+            const pointerdown = new PointerEvent('pointerdown', {pointerId: 1, pointerType: 'touch'});
+            const pointerup = new PointerEvent('pointerdown', {pointerId: 1, pointerType: 'touch'});
+            Blockly.Touch.shouldHandleEvent(pointerdown);
+            chai.assert.isTrue(Blockly.Touch.shouldHandleEvent(pointerup));
+        });
+    });
+
+    suite('getTouchIdentifierFromEvent', function() {
+        test('is mouse for MouseEvents', function() {
+            const mousedown = new MouseEvent('mousedown');
+            chai.assert.equal(Blockly.Touch.getTouchIdentifierFromEvent(mousedown), 'mouse');
+        });
+
+        test('is pointerId for mouse PointerEvents', function() {
+            const pointerdown = new PointerEvent('pointerdown', {pointerId: 7, pointerType: 'mouse'});
+            chai.assert.equal(Blockly.Touch.getTouchIdentifierFromEvent(pointerdown), 7);
+        });
+
+        test('is pointerId for touch PointerEvents', function() {
+            const pointerdown = new PointerEvent('pointerdown', {pointerId: 42, pointerType: 'touch'});
+            chai.assert.equal(Blockly.Touch.getTouchIdentifierFromEvent(pointerdown), 42);
+        });
+    });
+ });