Update docs and prop types

Author: Marek Rozmus

README.md

@@ -63,6 +63,12 @@ NOTE: `SwipeableListItem` can be used without `SwipeableList` but swipe blocking
 
 ## SwipeableList Props
 
+### scrollElement
+
+Type: `EventTarget`
+
+Required to block swipe during scrolling outside of list e.g. set to `window` to block swiping during body scroll.
+
 ### threshold
 
 Type: `number`

src/SwipeableList.js

@@ -51,7 +51,10 @@ const SwipeableList = ({ children, scrollElement, threshold }) => {
 
 SwipeableList.propTypes = {
   children: PropTypes.node,
-  scrollElement: PropTypes.instanceOf(EventTarget),
+  scrollElement:
+    typeof EventTarget !== 'undefined'
+      ? PropTypes.instanceOf(EventTarget)
+      : PropTypes.any,
   threshold: PropTypes.number
 };