Fixed #401: width of range items not always being maintained when moving due to snapping to nice dates

HISTORY.md

@@ -21,6 +21,8 @@ http://visjs.org
 
 - Implemented option `timeAxis: {scale: string, step: number}` to set a
   fixed scale.
+- Fixed width of range items not always being maintained when moving due to
+  snapping to nice dates.
 
 
 ## 2015-01-16, version 3.9.1

lib/timeline/component/ItemSet.js

@@ -1130,8 +1130,15 @@ ItemSet.prototype._onDragStart = function (event) {
         };
 
         if (me.options.editable.updateTime) {
-          if ('start' in item.data) props.start = item.data.start.valueOf();
-          if ('end' in item.data)   props.end = item.data.end.valueOf();
+          if ('start' in item.data) {
+            props.start = item.data.start.valueOf();
+
+            if ('end' in item.data) {
+              // we store a duration here in order not to change the width
+              // of the item when moving it.
+              props.duration = item.data.end.valueOf() - props.start;
+            }
+          }
         }
         if (me.options.editable.updateGroup) {
           if ('group' in item.data) props.group = item.data.group;
@@ -1151,7 +1158,7 @@ ItemSet.prototype._onDragStart = function (event) {
  * @private
  */
 ItemSet.prototype._onDrag = function (event) {
-  event.preventDefault()
+  event.preventDefault();
 
   if (this.touchParams.itemProps) {
     var me = this;
@@ -1174,6 +1181,9 @@ ItemSet.prototype._onDrag = function (event) {
         var end = new Date(props.end + offset);
         newProps.end = snap ? snap(end) : end;
       }
+      else if ('duration' in props) {
+        newProps.end = new Date(newProps.start.valueOf() + props.duration);
+      }
 
       if ('group' in props) {
         // drag from one group to another