diff --git a/lib/network/modules/LayoutEngine.js b/lib/network/modules/LayoutEngine.js
index ad907ebd8..7fb58aa51 100644
--- a/lib/network/modules/LayoutEngine.js
+++ b/lib/network/modules/LayoutEngine.js
@@ -711,7 +711,7 @@ class LayoutEngine {
       this.lastNodeOnLevel = {};
       this.hierarchical = new HierarchicalStatus();
 
-      for (nodeId in this.body.nodes) {
+      for (nodeId of this.body.nodeIndices) {
         if (this.body.nodes.hasOwnProperty(nodeId)) {
           node = this.body.nodes[nodeId];
           if (node.options.level !== undefined) {
@@ -746,7 +746,7 @@ class LayoutEngine {
 
 
         // fallback for cases where there are nodes but no edges
-        for (let nodeId in this.body.nodes) {
+        for (let nodeId of this.body.nodeIndices) {
           if (this.body.nodes.hasOwnProperty(nodeId)) {
             this.hierarchical.ensureLevel(nodeId);
           }
@@ -1106,7 +1106,7 @@ class LayoutEngine {
 
     // center all parents
     let centerAllParents = () => {
-      for (let nodeId in this.body.nodes) {
+      for (let nodeId of this.body.nodeIndices) {
         if (this.body.nodes.hasOwnProperty(nodeId))
           this._centerParent(this.body.nodes[nodeId]);
       }