diff --git a/src/App.jsx b/src/App.jsx
index ae2dc9f..e68c527 100644
--- a/src/App.jsx
+++ b/src/App.jsx
@@ -489,7 +489,7 @@ function App() {
     nodes.forEach(node => {
       const newInd = nodesIndexes.get(node.id)
       if (node && node.data.type === 'input' || node.data.type === 'const') {
-        for (let i = 0; i < newInd.length; i++) {
+        for (let i = 0; i < newInd?.length; i++) {
           xml += `            <inVariable localId="${newInd[i]}" width="${node.data.width}" height="${node.data.height}">\n`
           xml += `              <position x="${Math.round(node.position.x)}" y="${Math.round(node.position.y)}"/>\n`
           xml += `              <connectionPointOut/>\n`
@@ -502,7 +502,7 @@ function App() {
     nodes.forEach(node => {
       const newInd = nodesIndexes.get(node.id)
       if (node.data.type === 'output') {
-        for (let i = 0; i < newInd.length; i++) {
+        for (let i = 0; i < newInd?.length; i++) {
           xml += `            <outVariable localId="${newInd[i]}" width="${node.data.width}" height="${node.data.height}">\n`
           xml += `              <position x="${Math.round(node.position.x)}" y="${Math.round(node.position.y)}"/>\n`
           xml += `              <connectionPointIn>\n`