Fixed #1527: error when creating/updating a Timeline without data

HISTORY.md

@@ -4,8 +4,9 @@ http://visjs.org
 
 ## not yet released, version 4.11.1-SNAPSHOT
 
+### Timeline
 
-
+- Fixed #1527: error when creating/updating a Timeline without data.
 
 
 ## 2015-12-18, version 4.11.0

lib/timeline/Timeline.js

@@ -379,8 +379,8 @@ Timeline.prototype.fit = function (options) {
 Timeline.prototype.getItemRange = function () {
   // get a rough approximation for the range based on the items start and end dates
   var range = this.getDataRange();
-  var min = range.min.valueOf();
-  var max = range.max.valueOf();
+  var min = range.min !== null ? range.min.valueOf() : null;
+  var max = range.max !== null ? range.max.valueOf() : null;
   var minItem = null;
   var maxItem = null;