Do not render widget if no basic MDX is set

Author: nikitaeverywhere

package.json

@@ -1,7 +1,7 @@
 {
   "name": "LightPivotTable",
   "author": "ZitRo",
-  "version": "1.4.11",
+  "version": "1.4.12",
   "description": "A lightweight pivot table for MDX2JSON source for InterSystems Cache",
   "main": "test/testServer.js",
   "repository": {

source/js/LightPivotTable.js

@@ -50,6 +50,11 @@ LightPivotTable.prototype.refresh = function () {
     var _  = this,
         i;
 
+    if (!this.dataSource.BASIC_MDX) {
+        console.log("Unable to refresh: no basic MDX set.");
+        return;
+    }
+
     this.clearFilters();
     if (this.CONFIG["defaultFilterSpecs"] instanceof Array) {
         for (i in this.CONFIG["defaultFilterSpecs"]) {