diff --git a/src/onTap.js b/src/onTap.js
index cd41eca..8ff9ba2 100644
--- a/src/onTap.js
+++ b/src/onTap.js
@@ -1,4 +1,4 @@
-import {hypotenuse, noop} from './utils.js';
+import {has, hypotenuse, noop} from './utils.js';
 
 const MODULE = 'onTap';
 
@@ -240,9 +240,10 @@ export default class OnTap {
 		if (this.state.tapStartTime) {
 			const touches = [...event.touches];
 
-			event.scale = event.scale ? event.scale :
-				touches.length < 2 ? 1 :
-				hypotenuse(touches[0].pageX - touches[1].pageX, touches[0].pageY - touches[1].pageY) / this.state.scaleStart;
+			if (!has(event, 'scale')) {
+				event.scale = touches.length < 2 ? 1 :
+					hypotenuse(touches[0].pageX - touches[1].pageX, touches[0].pageY - touches[1].pageY) / this.state.scaleStart;
+			}
 
 			Object.assign(event, {
 				offsetX: touches.reduce((memo, touch) => memo + touch.pageX, 0) / touches.length,
diff --git a/src/utils.js b/src/utils.js
index 1f461eb..fbb57a3 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -34,7 +34,7 @@ export function clone(obj) {
 }
 
 export function has(obj, prop) {
-	return obj && obj.hasOwnProperty(prop);
+	return obj && (obj.hasOwnProperty(prop) || (prop in obj));
 }
 
 export function hypotenuse(a, b) {