diff --git a/src/plugins/vis_builder/public/visualizations/vega/utils/helpers.ts b/src/plugins/vis_builder/public/visualizations/vega/utils/helpers.ts
index 54df11fb25b5..98390199a480 100644
--- a/src/plugins/vis_builder/public/visualizations/vega/utils/helpers.ts
+++ b/src/plugins/vis_builder/public/visualizations/vega/utils/helpers.ts
@@ -79,7 +79,7 @@ const flattenSeries = (
   });
 };
 
-const flattenHierarchy = (data, parentId = null, parentValue = null, level = 0) => {
+const flattenHierarchy = (data, split = null, parentId = null, parentValue = null, level = 0) => {
   let result = [];
 
   data.forEach((item, index) => {
@@ -92,10 +92,13 @@ const flattenHierarchy = (data, parentId = null, parentValue = null, level = 0)
       value: item.value,
       parentValue,
       level,
+      split,
     });
 
     if (item.children && item.children.length > 0) {
-      result = result.concat(flattenHierarchy(item.children, currentId, item.value, level + 1));
+      result = result.concat(
+        flattenHierarchy(item.children, split, currentId, item.value, level + 1)
+      );
     }
   });
 
@@ -123,13 +126,11 @@ export const flattenDataHandler = (context, dimensions, handlerType = 'series')
       converted.series = flattenSeries(converted.series);
     }
   } else if (handlerType === 'slices') {
-    // if (group && group.length !== 0) {
-    //   converted.series = group.slices.children.map(slice => ({
-    //     name: slice.name,
-    //     size: slice.size
-    //   }));
-    // } else {
-    converted.slices = flattenHierarchy(converted.slices);
+    if (group && group.length !== 0) {
+      // TODO:
+    } else {
+      converted.slices = flattenHierarchy(converted.slices);
+    }
   }
 
   return converted;