fix: var assigner input node can not find caused error (#3274)

web/app/components/workflow/utils.ts

@@ -214,14 +214,19 @@ export const getNodesConnectedSourceOrTargetHandleIdsMap = (changes: ConnectedSo
       type,
     } = change
     const sourceNode = nodes.find(node => node.id === edge.source)!
-    nodesConnectedSourceOrTargetHandleIdsMap[sourceNode.id] = nodesConnectedSourceOrTargetHandleIdsMap[sourceNode.id] || {
-      _connectedSourceHandleIds: [...(sourceNode?.data._connectedSourceHandleIds || [])],
-      _connectedTargetHandleIds: [...(sourceNode?.data._connectedTargetHandleIds || [])],
+    if (sourceNode) {
+      nodesConnectedSourceOrTargetHandleIdsMap[sourceNode.id] = nodesConnectedSourceOrTargetHandleIdsMap[sourceNode.id] || {
+        _connectedSourceHandleIds: [...(sourceNode?.data._connectedSourceHandleIds || [])],
+        _connectedTargetHandleIds: [...(sourceNode?.data._connectedTargetHandleIds || [])],
+      }
     }
+
     const targetNode = nodes.find(node => node.id === edge.target)!
-    nodesConnectedSourceOrTargetHandleIdsMap[targetNode.id] = nodesConnectedSourceOrTargetHandleIdsMap[targetNode.id] || {
-      _connectedSourceHandleIds: [...(targetNode?.data._connectedSourceHandleIds || [])],
-      _connectedTargetHandleIds: [...(targetNode?.data._connectedTargetHandleIds || [])],
+    if (targetNode) {
+      nodesConnectedSourceOrTargetHandleIdsMap[targetNode.id] = nodesConnectedSourceOrTargetHandleIdsMap[targetNode.id] || {
+        _connectedSourceHandleIds: [...(targetNode?.data._connectedSourceHandleIds || [])],
+        _connectedTargetHandleIds: [...(targetNode?.data._connectedTargetHandleIds || [])],
+      }
     }
 
     if (sourceNode) {