Fixed #1486: Item range sometimes wrongly calculated on IE in case of old dates

HISTORY.md

@@ -14,6 +14,7 @@ http://visjs.org
   data in a DataSet or DataView.
 - Fixed #1491: Problem using ctrl+drag in combination with using a `DataView`,
   and an issue with ctrl+drag when using `snap: null`.
+- Fixed #1486: Item range sometimes wrongly calculated on IE in case of old dates.
 
 ### Graph2d
 

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;
-  var max = range.max;
+  var min = range.min.valueOf();
+  var max = range.max.valueOf();
   var minItem = null;
   var maxItem = null;
 
@@ -407,8 +407,8 @@ Timeline.prototype.getItemRange = function () {
       var start = getStart(item);
       var end = getEnd(item);
 
-      var left  = new Date(start - (item.getWidthLeft() + 10) * factor);
-      var right = new Date(end   + (item.getWidthRight() + 10) * factor);
+      var left  = start - (item.getWidthLeft()  + 10) * factor;
+      var right = end   + (item.getWidthRight() + 10) * factor;
 
       if (left < min) {
         min = left;