asc_getType return type or default type if not exist

cell/model/WorkbookElems.js

@@ -4829,7 +4829,7 @@ CellArea.prototype = {
 		return this.Id;
 	};
 	sparklineGroup.prototype.asc_getType = function () {
-		return this.type;
+		return null !== this.type ? this.type : Asc.c_oAscSparklineType.Line;
 	};
 	sparklineGroup.prototype.asc_getLineWeight = function () {
 		return this.lineWeight;

common/Charts/DrawingObjects.js

@@ -627,7 +627,7 @@ CSparklineView.prototype.initFromSparkline = function(oSparkline, oSparklineGrou
     AscFormat.ExecuteNoHistory(function(){
         this.ws = worksheetView;
         var settings = new AscCommon.asc_ChartSettings();
-        var nSparklineType = AscFormat.isRealNumber(oSparklineGroup.type) ? oSparklineGroup.type : Asc.c_oAscSparklineType.Line;
+        var nSparklineType = oSparklineGroup.asc_getType();
         switch(nSparklineType)
         {
             case Asc.c_oAscSparklineType.Column: