added event handlers for onAddGroup, onMoveGroup, onRemoveGroup

lib/timeline/component/ItemSet.js

@@ -76,6 +76,15 @@ function ItemSet(body, options) {
     onMoving: function (item, callback) {
       callback(item);
     },
+    onAddGroup: function (item, callback) {
+      callback(item);
+    },
+    onMoveGroup: function (item, callback) {
+      callback(item);
+    },
+    onRemoveGroup: function (item, callback) {
+      callback(item);
+    },
 
     margin: {
       item: {
@@ -365,7 +374,7 @@ ItemSet.prototype.setOptions = function(options) {
         this.options[name] = fn;
       }
     }).bind(this);
-    ['onAdd', 'onUpdate', 'onRemove', 'onMove', 'onMoving'].forEach(addCallback);
+    ['onAdd', 'onUpdate', 'onRemove', 'onMove', 'onMoving', 'onAddGroup', 'onMoveGroup', 'onRemoveGroup'].forEach(addCallback);
 
     // force the itemSet to refresh: options like orientation and margins may be changed
     this.markDirty();
@@ -1534,7 +1543,59 @@ ItemSet.prototype._onGroupDragEnd = function (event) {
 	if (this.options.groupEditable.order && this.groupTouchParams.group) {
 		event.stopPropagation();
 		
-		this.body.emitter.emit('groupDragged');
+		// update existing group
+		var me = this;
+		var id = me.groupTouchParams.group.groupId;
+		var dataset = me.groupsData.getDataSet();
+        var groupData = util.extend({}, dataset.get(id)); // clone the data
+        me.options.onMoveGroup(groupData, function (groupData) {
+          if (groupData) {
+            // apply changes
+        	groupData[dataset._fieldId] = id; // ensure the group contains its id (can be undefined)
+            dataset.update(groupData);
+          }
+          else {
+        	  
+        	// fetch current order of groups
+  			var newOrder = dataset.getIds({
+  			    order: me.options.groupOrder
+  		    });
+        	  
+            // restore original order
+        	if (!util.equalArray(newOrder, me.groupTouchParams.originalOrder)) {
+        		var origOrder = me.groupTouchParams.originalOrder;
+  				var numGroups = Math.min(origOrder.length, newOrder.length);
+  				var curPos = 0;
+  				while (curPos < numGroups) {
+  					// as long as the groups are where they should be step down along the groups order
+  					while (curPos < numGroups && newOrder[curPos] == origOrder[curPos]) {
+  					    curPos++;
+  					}
+  					
+  					// all ok
+  					if (curPos >= numGroups) {
+  						break;
+  					}
+  					
+  					// found a group that has the wrong position -> switch with the 
+  					// group at the position where other one should be, fix index arrays and continue
+  					var slippedPosition = newOrder.indexOf(origOrder[curPos])
+  					var switchGroup = dataset.get(newOrder[curPos]);
+  					var shouldBeGroup = dataset.get(origOrder[curPos]);
+  					me.options.groupOrderSwap(switchGroup, shouldBeGroup, dataset);
+  						
+  					var switchGroupId = newOrder[curPos];
+  					newOrder[curPos] = origOrder[curPos];
+  					newOrder[slippedPosition] = switchGroupId;
+  						
+  					curPos++;
+  				}
+  			}
+
+          }
+          
+          me.body.emitter.emit('groupDragged');
+        });
 	}
 }
 

lib/timeline/optionsTimeline.js

@@ -97,6 +97,9 @@ let allOptions = {
   onMove: {'function': 'function'},
   onMoving: {'function': 'function'},
   onRemove: {'function': 'function'},
+  onAddGroup: {'function': 'function'},
+  onMoveGroup: {'function': 'function'},
+  onRemoveGroup: {'function': 'function'},
   order: {'function': 'function'},
   orientation: {
     axis: {string,'undefined': 'undefined'},