Add safeguard to handleTouchMove

2020-03-09 19:37:21 +02:00
parent 831c5f8c69
commit 85d84a0c40
1 changed files with 2 additions and 1 deletions
--- a/src/ol/MapBrowserEventHandler.js
+++ b/src/ol/MapBrowserEventHandler.js
@@ -275,7 +275,8 @@ class MapBrowserEventHandler extends EventTarget {
   * @private
   */
  handleTouchMove_(event) {
-    if (this.originalPointerMoveEvent_.defaultPrevented) {
+    // In some environments (such as iOS 12), this handler can get called once before the `originalPointerMoveEvent_` is initialized. This prevents crashes in those situations (but may not work correctly if `originalPointerMoveEvent_` lags behind the current event?).
+    if (this.originalPointerMoveEvent_ && this.originalPointerMoveEvent_.defaultPrevented) {
      event.preventDefault();
    }
  }