diff --git a/src/local_view/elements/map_node.ts b/src/local_view/elements/map_node.ts
index cd64f2b5..60f956dc 100644
--- a/src/local_view/elements/map_node.ts
+++ b/src/local_view/elements/map_node.ts
@@ -365,7 +365,7 @@ export class MapNode extends Node {
                     access.dataContainer
                 );
                 if (nodes) {
-                    const node = nodes.values().next().value[1];
+                    const node = nodes.values()?.next()?.value[1];
 
                     if (node && !access.index.includes(undefined)) {
                         const cl = node.getCacheLine(access.index as number[]);
diff --git a/src/local_view/elements/memory_node.ts b/src/local_view/elements/memory_node.ts
index b4280a13..7f5baef6 100644
--- a/src/local_view/elements/memory_node.ts
+++ b/src/local_view/elements/memory_node.ts
@@ -159,7 +159,7 @@ class MemoryTile extends Graphics {
                 const nodeRet =
                     this.memoryNode.parentGraph.memoryNodesMap.get(key);
                 if (nodeRet !== undefined && nodeRet.size) {
-                    const node = nodeRet.values().next().value[1];
+                    const node = nodeRet.values()?.next()?.value[1];
 
                     val.forEach(v => {
                         node.applyToIdx(
diff --git a/src/local_view/graph/graph.ts b/src/local_view/graph/graph.ts
index e2eb92e0..f0eb7636 100644
--- a/src/local_view/graph/graph.ts
+++ b/src/local_view/graph/graph.ts
@@ -87,7 +87,7 @@ export class Graph extends Graphics {
     public contractGraph(): void {
         const contractionRegions = this.findContractionRegions();
         for (const region of contractionRegions) {
-            const regionId = region.values().next().value.id;
+            const regionId = region.values()?.next()?.value.id;
             const regionInEdges = new Set<Edge>();
             const regionOutEdges = new Set<Edge>();
             const removedContainers = new Set<DataContainer>();