Fix race condition when unregister an event inside handlers

src/Node.ts

@@ -2379,18 +2379,18 @@ export abstract class Node<Config extends NodeConfig = NodeConfig> {
 
     const topListeners = this._getProtoListeners(eventType);
     if (topListeners) {
-      for (var i = 0; i < topListeners.length; i++) {
-        topListeners[i].handler.call(this, evt);
-      }
+      topListeners.slice(0).forEach((listener) => {
+        listener.handler.call(this, evt);
+      });
     }
 
     // it is important to iterate over self listeners without cache
     // because events can be added/removed while firing
     const selfListeners = this.eventListeners[eventType];
     if (selfListeners) {
-      for (var i = 0; i < selfListeners.length; i++) {
-        selfListeners[i].handler.call(this, evt);
-      }
+      selfListeners.slice(0).forEach((listener) => {
+        listener.handler.call(this, evt);
+      });
     }
   }
   /**

test/unit/Node-test.ts

@@ -2004,7 +2004,7 @@ describe('Node', function () {
   });
 
   // ======================================================
-  it('remove event with with callback', function () {
+  it('remove event with callback', function () {
     var stage = addStage();
     var layer = new Konva.Layer();
     var circle = new Konva.Circle({
@@ -2045,6 +2045,47 @@ describe('Node', function () {
     assert.equal(event2, 2, 'event2 triggered twice');
   });
 
+  // ======================================================
+  it('remove and add event inside callback handler', function () {
+    var stage = addStage();
+    var layer = new Konva.Layer();
+    var circle = new Konva.Circle();
+    stage.add(layer);
+    layer.add(circle);
+    layer.draw();
+
+    var event1 = 0;
+    var event2 = 0;
+    var event3 = 0;
+
+    var callback1 = function () {
+      event1 += 1;
+      circle.off('event', callback1);
+      circle.on('event', callback3);
+    };
+    var callback2 = function () {
+      event2 += 1;
+    };
+    var callback3 = function () {
+      event3 += 1;
+    };
+
+    circle.on('event', callback1);
+    circle.on('event', callback2);
+
+    circle.fire('event');
+
+    assert.equal(event1, 1, 'event1 triggered once');
+    assert.equal(event2, 1, 'event2 triggered once');
+    assert.equal(event3, 0, 'event2 not triggered');
+
+    circle.fire('event');
+
+    assert.equal(event1, 1, 'event1 still triggered once');
+    assert.equal(event2, 2, 'event2 triggered twice');
+    assert.equal(event3, 1, 'event3 triggered once');
+  });
+
   // ======================================================
   it('simulate event bubble', function () {
     var stage = addStage();