Additional minor fixes.

Author: MKirova

projects/igniteui-angular/src/lib/grids/pivot-grid/pivot-grid.pipes.ts

@@ -30,7 +30,7 @@ export class IgxPivotRowPipe implements PipeTransform {
     ): any[] {
         const enabledRows = config.rows.filter(x => x.enabled);
         const rowStrategy = config.rowStrategy ||  PivotRowDimensionsStrategy.instance();
-        return rowStrategy.process(collection.slice(0), enabledRows, config.values, pivotKeys);
+        return rowStrategy.process(cloneArray(collection, true), enabledRows, config.values, pivotKeys);
     }
 }
 

projects/igniteui-angular/src/lib/grids/pivot-grid/pivot-util.ts

@@ -114,7 +114,7 @@ export class PivotUtil {
                     data.splice(i, 1, ...dimData);
                     i += dimData.length - 1;
                 }
-            } else {
+            } else if (isExpanded) {
                 // this is leaf
                 let leafDim = dim;
                 let currLvl = currDimLvl;
@@ -123,7 +123,7 @@ export class PivotUtil {
                     currLvl++;
                 }
                 rec[leafDim.memberName + '_' + pivotKeys.level] = currLvl;
-                rec[field + '_' + pivotKeys.level] = undefined;
+                delete rec[field + '_' + pivotKeys.level];
             }
         }
         return data;