Only consider touch events to compute ol.interaction.Touch.targetTouches

src/ol/interaction/touchinteraction.js

@@ -1,6 +1,7 @@
 
 goog.provide('ol.interaction.Touch');
 
+goog.require('goog.asserts');
 goog.require('goog.functions');
 goog.require('goog.object');
 goog.require('ol.MapBrowserEvent');
@@ -57,17 +58,33 @@ ol.interaction.Touch.centroid = function(touches) {
 };
 
 
+/**
+ * @param {ol.MapBrowserEvent} mapBrowserEvent Event.
+ * @return {boolean} Whether the event is a touchstart, touchmove
+ *     or touchend event.
+ * @private
+ */
+ol.interaction.Touch.isTouchEvent_ = function(mapBrowserEvent) {
+  var type = mapBrowserEvent.type;
+  return (
+      type === ol.MapBrowserEvent.EventType.TOUCHSTART ||
+      type === ol.MapBrowserEvent.EventType.TOUCHMOVE ||
+      type === ol.MapBrowserEvent.EventType.TOUCHEND);
+};
+
+
 /**
  * @param {ol.MapBrowserEvent} mapBrowserEvent Event.
  * @private
  */
 ol.interaction.Touch.prototype.updateTrackedTouches_ =
     function(mapBrowserEvent) {
+  if (ol.interaction.Touch.isTouchEvent_(mapBrowserEvent)) {
     var event = mapBrowserEvent.browserEvent.getBrowserEvent();
     if (goog.isDef(event.targetTouches)) {
       // W3C touch events
       this.targetTouches = event.targetTouches;
-  } else {
+    } else if (goog.isDef(event.pointerId)) {
       // IE pointer event
       if (mapBrowserEvent.type == ol.MapBrowserEvent.EventType.TOUCHEND) {
         delete this.trackedTouches_[event.pointerId];
@@ -75,6 +92,9 @@ ol.interaction.Touch.prototype.updateTrackedTouches_ =
         this.trackedTouches_[event.pointerId] = event;
       }
       this.targetTouches = goog.object.getValues(this.trackedTouches_);
+    } else {
+      goog.asserts.fail('unknown touch event model');
+    }
   }
 };