fix: config parameter modified by toKonvaCanvas

src/Layer.ts

@@ -228,7 +228,7 @@ export class Layer extends Container<Group | Shape> {
     }
   }
   _toKonvaCanvas(config) {
-    config = config || {};
+    config = { ...config };
     config.width = config.width || this.getWidth();
     config.height = config.height || this.getHeight();
     config.x = config.x !== undefined ? config.x : this.x();

src/Stage.ts

@@ -316,7 +316,7 @@ export class Stage extends Container<Layer> {
     return this.content;
   }
   _toKonvaCanvas(config) {
-    config = config || {};
+    config = { ...config };
 
     config.x = config.x || 0;
     config.y = config.y || 0;