From 9d988432138a8e1da4ec1fc5dcdd0a006f95c09b Mon Sep 17 00:00:00 2001
From: Pascal Delange <pascal@checkmarble.com>
Date: Thu, 21 Nov 2024 12:46:52 +0100
Subject: [PATCH] fix error on ast state machine

better
---
 .../app-builder/src/services/editor/ast-editor.tsx   | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/packages/app-builder/src/services/editor/ast-editor.tsx b/packages/app-builder/src/services/editor/ast-editor.tsx
index 0066f531..bc9c8e69 100644
--- a/packages/app-builder/src/services/editor/ast-editor.tsx
+++ b/packages/app-builder/src/services/editor/ast-editor.tsx
@@ -91,10 +91,9 @@ export function useAstNodeEditor({
             name,
           };
           if (isUnaryMainAstOperatorFunction(name)) {
-            const children = newNode.children.slice(0, 1);
-            newNode.children = children;
+            newNode.children = newNChildren(1, newNode.children);
           } else if (isBinaryMainAstOperatorFunction(name)) {
-            newNode.children.push(NewUndefinedAstNode());
+            newNode.children = newNChildren(2, newNode.children);
           }
           set({
             rootAstNode: setAtPath(rootAstNode, path, newNode),
@@ -134,6 +133,13 @@ export function useAstNodeEditor({
   return store;
 }
 
+function newNChildren(n: number, currentChildren: AstNode[]) {
+  return Array.from(
+    { length: n },
+    (_, i) => currentChildren[i] ?? NewUndefinedAstNode(),
+  );
+}
+
 export function AstNodeEditorProvider({
   children,
   store,