fix: Load workflows with unconnected Switch outputs (#12020)

cypress/composables/workflow.ts

@@ -76,6 +76,10 @@ export function getCanvasNodes() {
 	);
 }
 
+export function getCanvasNodeByName(nodeName: string) {
+	return getCanvasNodes().filter(`:contains(${nodeName})`);
+}
+
 export function getSaveButton() {
 	return cy.getByTestId('workflow-save-button');
 }
@@ -194,3 +198,8 @@ export function pasteWorkflow(workflow: object) {
 export function clickZoomToFit() {
 	getZoomToFitButton().click();
 }
+
+export function deleteNode(name: string) {
+	getCanvasNodeByName(name).first().click();
+	cy.get('body').type('{del}');
+}

cypress/e2e/2929-ado-can-load-old-switch-node-workflows.cy.ts

@@ -0,0 +1,17 @@
+import {
+	deleteNode,
+	getCanvasNodes,
+	navigateToNewWorkflowPage,
+	pasteWorkflow,
+} from '../composables/workflow';
+import Workflow from '../fixtures/Switch_node_with_null_connection.json';
+
+describe('ADO-2929 can load Switch nodes', () => {
+	it('can load workflows with Switch nodes with null at connection index', () => {
+		navigateToNewWorkflowPage();
+		pasteWorkflow(Workflow);
+		getCanvasNodes().should('have.length', 3);
+		deleteNode('Switch');
+		getCanvasNodes().should('have.length', 2);
+	});
+});

cypress/fixtures/Switch_node_with_null_connection.json

@@ -0,0 +1,85 @@
+{
+	"nodes": [
+		{
+			"parameters": {},
+			"id": "418350b8-b402-4d3b-93ba-3794d36c1ad5",
+			"name": "When clicking \"Test workflow\"",
+			"type": "n8n-nodes-base.manualTrigger",
+			"typeVersion": 1,
+			"position": [440, 380]
+		},
+		{
+			"parameters": {
+				"rules": {
+					"values": [
+						{
+							"conditions": {
+								"options": {
+									"caseSensitive": true,
+									"leftValue": "",
+									"typeValidation": "strict"
+								},
+								"conditions": [
+									{
+										"leftValue": "",
+										"rightValue": "",
+										"operator": {
+											"type": "string",
+											"operation": "equals"
+										}
+									}
+								],
+								"combinator": "and"
+							}
+						},
+						{},
+						{}
+					]
+				},
+				"options": {}
+			},
+			"id": "b67ad46f-6b0d-4ff4-b2d2-dfbde44e287c",
+			"name": "Switch",
+			"type": "n8n-nodes-base.switch",
+			"typeVersion": 3,
+			"position": [660, 380]
+		},
+		{
+			"parameters": {
+				"options": {}
+			},
+			"id": "24731c11-e2a4-4854-81a6-277ce72e8a93",
+			"name": "Edit Fields",
+			"type": "n8n-nodes-base.set",
+			"typeVersion": 3.3,
+			"position": [840, 480]
+		}
+	],
+	"connections": {
+		"When clicking \"Test workflow\"": {
+			"main": [
+				[
+					{
+						"node": "Switch",
+						"type": "main",
+						"index": 0
+					}
+				]
+			]
+		},
+		"Switch": {
+			"main": [
+				null,
+				null,
+				[
+					{
+						"node": "Edit Fields",
+						"type": "main",
+						"index": 0
+					}
+				]
+			]
+		}
+	},
+	"pinData": {}
+}

packages/cli/src/databases/migrations/common/1675940580449-PurgeInvalidWorkflowConnections.ts

@@ -38,7 +38,7 @@ export class PurgeInvalidWorkflowConnections1675940580449 implements Irreversibl
 
 						// It filters out all connections that are connected to a node that cannot receive input
 						outputConnection.forEach((outputConnectionItem, outputConnectionItemIdx) => {
-							outputConnection[outputConnectionItemIdx] = outputConnectionItem.filter(
+							outputConnection[outputConnectionItemIdx] = (outputConnectionItem ?? []).filter(
 								(outgoingConnections) =>
 									!nodesThatCannotReceiveInput.includes(outgoingConnections.node),
 							);

packages/cli/src/security-audit/risk-reporters/instance-risk-reporter.ts

@@ -119,7 +119,7 @@ export class InstanceRiskReporter implements RiskReporter {
 		node: WorkflowEntity['nodes'][number];
 		workflow: WorkflowEntity;
 	}) {
-		const childNodeNames = workflow.connections[node.name]?.main[0].map((i) => i.node);
+		const childNodeNames = workflow.connections[node.name]?.main[0]?.map((i) => i.node);
 
 		if (!childNodeNames) return false;
 

packages/core/src/PartialExecutionUtils/DirectedGraph.ts

@@ -448,7 +448,7 @@ export class DirectedGraph {
 
 			for (const [outputType, outputs] of Object.entries(iConnection)) {
 				for (const [outputIndex, conns] of outputs.entries()) {
-					for (const conn of conns) {
+					for (const conn of conns ?? []) {
 						// TODO: What's with the input type?
 						const { node: toNodeName, type: _inputType, index: inputIndex } = conn;
 						const to = workflow.getNode(toNodeName);

packages/core/src/PartialExecutionUtils/__tests__/DirectedGraph.test.ts

@@ -42,6 +42,28 @@ describe('DirectedGraph', () => {
 		);
 	});
 
+	//    ┌─────┐    ┌─────┐──► null
+	//    │node1├───►│node2|   ┌─────┐
+	//    └─────┘    └─────┘──►│node3|
+	//                         └─────┘
+	//
+	test('linear workflow with null connections', () => {
+		// ARRANGE
+		const node1 = createNodeData({ name: 'Node1' });
+		const node2 = createNodeData({ name: 'Node2' });
+		const node3 = createNodeData({ name: 'Node3' });
+
+		// ACT
+		const graph = new DirectedGraph()
+			.addNodes(node1, node2, node3)
+			.addConnections({ from: node1, to: node2 }, { from: node2, to: node3, outputIndex: 1 });
+
+		// ASSERT
+		expect(DirectedGraph.fromWorkflow(graph.toWorkflow({ ...defaultWorkflowParameter }))).toEqual(
+			graph,
+		);
+	});
+
 	describe('getChildren', () => {
 		// ┌─────┐    ┌─────┐   ┌─────┐
 		// │node1├───►│node2├──►│node3│

packages/core/src/WorkflowExecute.ts

@@ -36,6 +36,7 @@ import type {
 	CloseFunction,
 	StartNodeData,
 	NodeExecutionHint,
+	NodeInputConnections,
 } from 'n8n-workflow';
 import {
 	LoggerProxy as Logger,
@@ -208,6 +209,9 @@ export class WorkflowExecute {
 				// Get the data of the incoming connections
 				incomingSourceData = { main: [] };
 				for (const connections of incomingNodeConnections.main) {
+					if (!connections) {
+						continue;
+					}
 					for (let inputIndex = 0; inputIndex < connections.length; inputIndex++) {
 						connection = connections[inputIndex];
 
@@ -249,6 +253,9 @@ export class WorkflowExecute {
 				incomingNodeConnections = workflow.connectionsByDestinationNode[destinationNode];
 				if (incomingNodeConnections !== undefined) {
 					for (const connections of incomingNodeConnections.main) {
+						if (!connections) {
+							continue;
+						}
 						for (let inputIndex = 0; inputIndex < connections.length; inputIndex++) {
 							connection = connections[inputIndex];
 
@@ -642,7 +649,7 @@ export class WorkflowExecute {
 					}
 					for (const connectionDataCheck of workflow.connectionsBySourceNode[parentNodeName].main[
 						outputIndexParent
-					]) {
+					] ?? []) {
 						checkOutputNodes.push(connectionDataCheck.node);
 					}
 				}
@@ -661,7 +668,7 @@ export class WorkflowExecute {
 				) {
 					for (const inputData of workflow.connectionsByDestinationNode[connectionData.node].main[
 						inputIndex
-					]) {
+					] ?? []) {
 						if (inputData.node === parentNodeName) {
 							// Is the node we come from so its data will be available for sure
 							continue;
@@ -681,7 +688,7 @@ export class WorkflowExecute {
 							if (
 								!this.incomingConnectionIsEmpty(
 									this.runExecutionData.resultData.runData,
-									workflow.connectionsByDestinationNode[inputData.node].main[0],
+									workflow.connectionsByDestinationNode[inputData.node].main[0] ?? [],
 									runIndex,
 								)
 							) {
@@ -770,7 +777,7 @@ export class WorkflowExecute {
 						} else if (
 							this.incomingConnectionIsEmpty(
 								this.runExecutionData.resultData.runData,
-								workflow.connectionsByDestinationNode[nodeToAdd].main[0],
+								workflow.connectionsByDestinationNode[nodeToAdd].main[0] ?? [],
 								runIndex,
 							)
 						) {
@@ -1066,7 +1073,7 @@ export class WorkflowExecute {
 					if (workflow.connectionsByDestinationNode.hasOwnProperty(executionNode.name)) {
 						// Check if the node has incoming connections
 						if (workflow.connectionsByDestinationNode[executionNode.name].hasOwnProperty('main')) {
-							let inputConnections: IConnection[][];
+							let inputConnections: NodeInputConnections;
 							let connectionIndex: number;
 
 							// eslint-disable-next-line prefer-const
@@ -1586,7 +1593,7 @@ export class WorkflowExecute {
 								// Iterate over all the different connections of this output
 								for (connectionData of workflow.connectionsBySourceNode[executionNode.name].main[
 									outputIndex
-								]) {
+								] ?? []) {
 									if (!workflow.nodes.hasOwnProperty(connectionData.node)) {
 										throw new ApplicationError('Destination node not found', {
 											extra: {

packages/editor-ui/package.json

@@ -7,6 +7,7 @@
     "clean": "rimraf dist .turbo",
     "build": "cross-env VUE_APP_PUBLIC_PATH=\"/{{BASE_PATH}}/\" NODE_OPTIONS=\"--max-old-space-size=8192\" vite build",
     "typecheck": "vue-tsc --noEmit",
+    "typecheck:watch": "vue-tsc --watch --noEmit",
     "dev": "pnpm serve",
     "lint": "eslint src --ext .js,.ts,.vue --quiet",
     "lintfix": "eslint src --ext .js,.ts,.vue --fix",

packages/editor-ui/src/components/CanvasChat/composables/useChatMessaging.ts

@@ -256,7 +256,7 @@ export function useChatMessaging({
 			];
 		if (!connectedMemoryInputs) return [];
 
-		const memoryConnection = (connectedMemoryInputs ?? []).find((i) => i.length > 0)?.[0];
+		const memoryConnection = (connectedMemoryInputs ?? []).find((i) => (i ?? []).length > 0)?.[0];
 
 		if (!memoryConnection) return [];
 

packages/editor-ui/src/components/CodeNodeEditor/completions/jsonField.completions.ts

@@ -176,7 +176,7 @@ function useJsonFieldCompletions() {
 			if (activeNode) {
 				const workflow = workflowsStore.getCurrentWorkflow();
 				const input = workflow.connectionsByDestinationNode[activeNode.name];
-				return input.main[0][0].node;
+				return input.main[0] ? input.main[0][0].node : null;
 			}
 		} catch (e) {
 			console.error(e);

packages/editor-ui/src/components/InputNodeSelect.vue

@@ -86,7 +86,7 @@ function getMultipleNodesText(nodeName: string): string {
 		props.workflow.connectionsByDestinationNode[activeNode.value.name].main || [];
 	// Collect indexes of connected nodes
 	const connectedInputIndexes = activeNodeConnections.reduce((acc: number[], node, index) => {
-		if (node[0] && node[0].node === nodeName) return [...acc, index];
+		if (node?.[0] && node[0].node === nodeName) return [...acc, index];
 		return acc;
 	}, []);
 

packages/editor-ui/src/composables/useCanvasMapping.test.ts

@@ -238,7 +238,7 @@ describe('useCanvasMapping', () => {
 			expect(
 				mappedNodes.value[0]?.data?.connections[CanvasConnectionMode.Output][
 					NodeConnectionType.Main
-				][0][0],
+				][0]?.[0],
 			).toEqual(
 				expect.objectContaining({
 					node: setNode.name,
@@ -253,7 +253,7 @@ describe('useCanvasMapping', () => {
 			expect(
 				mappedNodes.value[1]?.data?.connections[CanvasConnectionMode.Input][
 					NodeConnectionType.Main
-				][0][0],
+				][0]?.[0],
 			).toEqual(
 				expect.objectContaining({
 					node: manualTriggerNode.name,

packages/editor-ui/src/composables/useCanvasOperations.test.ts

@@ -802,6 +802,82 @@ describe('useCanvasOperations', () => {
 			expect(workflowsStore.removeNodeExecutionDataById).toHaveBeenCalledWith(nodes[1].id);
 			expect(workflowsStore.removeNodeById).toHaveBeenCalledWith(nodes[1].id);
 		});
+
+		it('should handle nodes with null connections for unconnected indexes', () => {
+			const workflowsStore = mockedStore(useWorkflowsStore);
+			const nodeTypesStore = mockedStore(useNodeTypesStore);
+
+			nodeTypesStore.nodeTypes = {
+				[SET_NODE_TYPE]: { 1: mockNodeTypeDescription({ name: SET_NODE_TYPE }) },
+			};
+
+			const nodes = [
+				createTestNode({
+					id: 'input',
+					type: SET_NODE_TYPE,
+					position: [10, 20],
+					name: 'Input Node',
+				}),
+				createTestNode({
+					id: 'middle',
+					type: SET_NODE_TYPE,
+					position: [10, 20],
+					name: 'Middle Node',
+				}),
+				createTestNode({
+					id: 'output',
+					type: SET_NODE_TYPE,
+					position: [10, 20],
+					name: 'Output Node',
+				}),
+			];
+
+			workflowsStore.getNodeByName = vi
+				.fn()
+				.mockImplementation((name: string) => nodes.find((node) => node.name === name));
+
+			workflowsStore.workflow.nodes = nodes;
+			workflowsStore.workflow.connections = {
+				[nodes[0].name]: {
+					main: [
+						null,
+						[
+							{
+								node: nodes[1].name,
+								type: NodeConnectionType.Main,
+								index: 0,
+							},
+						],
+					],
+				},
+				[nodes[1].name]: {
+					main: [
+						// null here to simulate no connection at index
+						null,
+						[
+							{
+								node: nodes[2].name,
+								type: NodeConnectionType.Main,
+								index: 0,
+							},
+						],
+					],
+				},
+			};
+
+			const workflowObject = createTestWorkflowObject(workflowsStore.workflow);
+			workflowsStore.getCurrentWorkflow.mockReturnValue(workflowObject);
+			workflowsStore.incomingConnectionsByNodeName.mockReturnValue({});
+
+			workflowsStore.getNodeById.mockReturnValue(nodes[1]);
+
+			const { deleteNode } = useCanvasOperations({ router });
+			deleteNode(nodes[1].id);
+
+			expect(workflowsStore.removeNodeById).toHaveBeenCalledWith(nodes[1].id);
+			expect(workflowsStore.removeNodeExecutionDataById).toHaveBeenCalledWith(nodes[1].id);
+			expect(workflowsStore.removeNodeById).toHaveBeenCalledWith(nodes[1].id);
+		});
 	});
 
 	describe('revertDeleteNode', () => {

packages/editor-ui/src/composables/useCanvasOperations.ts

@@ -1149,11 +1149,9 @@ export function useCanvasOperations({ router }: { router: ReturnType<typeof useR
 
 			for (const type of Object.keys(connections[nodeName])) {
 				for (const index of Object.keys(connections[nodeName][type])) {
-					for (const connectionIndex of Object.keys(
-						connections[nodeName][type][parseInt(index, 10)],
-					)) {
-						const connectionData =
-							connections[nodeName][type][parseInt(index, 10)][parseInt(connectionIndex, 10)];
+					const connectionsToDelete = connections[nodeName][type][parseInt(index, 10)] ?? [];
+					for (const connectionIndex of Object.keys(connectionsToDelete)) {
+						const connectionData = connectionsToDelete[parseInt(connectionIndex, 10)];
 						if (!connectionData) {
 							continue;
 						}
@@ -1490,13 +1488,14 @@ export function useCanvasOperations({ router }: { router: ReturnType<typeof useR
 					sourceIndex++
 				) {
 					const nodeSourceConnections = [];
-					if (currentConnections[sourceNode][type][sourceIndex]) {
+					const connectionsToCheck = currentConnections[sourceNode][type][sourceIndex];
+					if (connectionsToCheck) {
 						for (
 							connectionIndex = 0;
-							connectionIndex < currentConnections[sourceNode][type][sourceIndex].length;
+							connectionIndex < connectionsToCheck.length;
 							connectionIndex++
 						) {
-							connectionData = currentConnections[sourceNode][type][sourceIndex][connectionIndex];
+							connectionData = connectionsToCheck[connectionIndex];
 							if (!createNodeNames.includes(connectionData.node)) {
 								// Node does not get created so skip input connection
 								continue;
@@ -1814,7 +1813,7 @@ export function useCanvasOperations({ router }: { router: ReturnType<typeof useR
 
 		for (const [type, typeConnections] of Object.entries(connections)) {
 			const validConnections = typeConnections.map((sourceConnections) =>
-				sourceConnections.filter((connection) => includeNodeNames.has(connection.node)),
+				(sourceConnections ?? []).filter((connection) => includeNodeNames.has(connection.node)),
 			);
 
 			if (validConnections.length) {

packages/editor-ui/src/composables/useWorkflowHelpers.ts

@@ -413,7 +413,7 @@ export function executeData(
 					mainConnections: for (const mainConnections of workflow.connectionsByDestinationNode[
 						currentNode
 					].main) {
-						for (const connection of mainConnections) {
+						for (const connection of mainConnections ?? []) {
 							if (
 								connection.type === NodeConnectionType.Main &&
 								connection.node === parentNodeName

packages/editor-ui/src/stores/ndv.store.ts

@@ -156,7 +156,7 @@ export const useNDVStore = defineStore(STORES.NDV, () => {
 		if (!activeNodeConections || activeNodeConections.length < 2) return returnData;
 
 		for (const [index, connection] of activeNodeConections.entries()) {
-			for (const node of connection) {
+			for (const node of connection ?? []) {
 				if (!returnData[node.node]) {
 					returnData[node.node] = [];
 				}

packages/editor-ui/src/stores/workflows.store.ts

@@ -891,23 +891,28 @@ export const useWorkflowsStore = defineStore(STORES.WORKFLOWS, () => {
 		let propertyName: keyof IConnection;
 		let connectionExists = false;
 
-		connectionLoop: for (const existingConnection of workflow.value.connections[sourceData.node][
-			sourceData.type
-		][sourceData.index]) {
-			for (propertyName of checkProperties) {
-				if (existingConnection[propertyName] !== destinationData[propertyName]) {
-					continue connectionLoop;
+		const nodeConnections = workflow.value.connections[sourceData.node][sourceData.type];
+		const connectionsToCheck = nodeConnections[sourceData.index];
+
+		if (connectionsToCheck) {
+			connectionLoop: for (const existingConnection of connectionsToCheck) {
+				for (propertyName of checkProperties) {
+					if (existingConnection[propertyName] !== destinationData[propertyName]) {
+						continue connectionLoop;
+					}
 				}
+				connectionExists = true;
+				break;
 			}
-			connectionExists = true;
-			break;
 		}
 
 		// Add the new connection if it does not exist already
 		if (!connectionExists) {
-			workflow.value.connections[sourceData.node][sourceData.type][sourceData.index].push(
-				destinationData,
-			);
+			nodeConnections[sourceData.index] = nodeConnections[sourceData.index] ?? [];
+			const connections = nodeConnections[sourceData.index];
+			if (connections) {
+				connections.push(destinationData);
+			}
 		}
 	}
 
@@ -934,6 +939,10 @@ export const useWorkflowsStore = defineStore(STORES.WORKFLOWS, () => {
 
 		const connections =
 			workflow.value.connections[sourceData.node][sourceData.type][sourceData.index];
+		if (!connections) {
+			return;
+		}
+
 		for (const index in connections) {
 			if (
 				connections[index].node === destinationData.node &&
@@ -979,23 +988,19 @@ export const useWorkflowsStore = defineStore(STORES.WORKFLOWS, () => {
 			for (type of Object.keys(workflow.value.connections[sourceNode])) {
 				for (sourceIndex of Object.keys(workflow.value.connections[sourceNode][type])) {
 					indexesToRemove.length = 0;
-					for (connectionIndex of Object.keys(
-						workflow.value.connections[sourceNode][type][parseInt(sourceIndex, 10)],
-					)) {
-						connectionData =
-							workflow.value.connections[sourceNode][type][parseInt(sourceIndex, 10)][
-								parseInt(connectionIndex, 10)
-							];
-						if (connectionData.node === node.name) {
-							indexesToRemove.push(connectionIndex);
+					const connectionsToRemove =
+						workflow.value.connections[sourceNode][type][parseInt(sourceIndex, 10)];
+					if (connectionsToRemove) {
+						for (connectionIndex of Object.keys(connectionsToRemove)) {
+							connectionData = connectionsToRemove[parseInt(connectionIndex, 10)];
+							if (connectionData.node === node.name) {
+								indexesToRemove.push(connectionIndex);
+							}
 						}
+						indexesToRemove.forEach((index) => {
+							connectionsToRemove.splice(parseInt(index, 10), 1);
+						});
 					}
-					indexesToRemove.forEach((index) => {
-						workflow.value.connections[sourceNode][type][parseInt(sourceIndex, 10)].splice(
-							parseInt(index, 10),
-							1,
-						);
-					});
 				}
 			}
 		}

packages/editor-ui/src/utils/nodeSettingsUtils.test.ts

@@ -56,7 +56,7 @@ describe('updateDynamicConnections', () => {
 		const updatedConnections = updateDynamicConnections(node, connections, parameterData);
 
 		expect(updatedConnections?.TestNode.main).toHaveLength(2);
-		expect(updatedConnections?.TestNode.main[1][0].node).toEqual('Node3');
+		expect(updatedConnections?.TestNode.main[1]?.[0].node).toEqual('Node3');
 	});
 
 	it('should handle fallbackOutput === "extra" and all rules removed', () => {
@@ -82,7 +82,7 @@ describe('updateDynamicConnections', () => {
 		const updatedConnections = updateDynamicConnections(node, connections, parameterData);
 
 		expect(updatedConnections?.TestNode.main).toHaveLength(1);
-		expect(updatedConnections?.TestNode.main[0][0].node).toEqual('Node3');
+		expect(updatedConnections?.TestNode.main[0]?.[0].node).toEqual('Node3');
 	});
 
 	it('should add a new connection when a rule is added', () => {
@@ -137,7 +137,7 @@ describe('updateDynamicConnections', () => {
 
 		expect(updatedConnections?.TestNode.main).toHaveLength(4);
 		expect(updatedConnections?.TestNode.main[2]).toEqual([]);
-		expect(updatedConnections?.TestNode.main[3][0].node).toEqual('Node3');
+		expect(updatedConnections?.TestNode.main[3]?.[0].node).toEqual('Node3');
 	});
 
 	it('should return null if no conditions are met', () => {

packages/editor-ui/src/utils/nodeSettingsUtils.ts

@@ -77,7 +77,7 @@ export function updateDynamicConnections(
 				}
 			} else if (parameterData.name === 'parameters.rules.values') {
 				const curentRulesvalues = (node.parameters?.rules as { values: IDataObject[] })?.values;
-				let lastConnection: IConnection[] | undefined = undefined;
+				let lastConnection: IConnection[] | null | undefined = undefined;
 				if (
 					fallbackOutput === 'extra' &&
 					connections[node.name].main.length === curentRulesvalues.length + 1

packages/editor-ui/src/views/NodeView.vue

@@ -1394,7 +1394,11 @@ export default defineComponent({
 					lastSelectedNode.name,
 				);
 
-				if (connections.main === undefined || connections.main.length === 0) {
+				if (
+					connections.main === undefined ||
+					connections.main.length === 0 ||
+					!connections.main[0]
+				) {
 					return;
 				}
 
@@ -1428,7 +1432,11 @@ export default defineComponent({
 
 				const connections = workflow.connectionsByDestinationNode[lastSelectedNode.name];
 
-				if (connections.main === undefined || connections.main.length === 0) {
+				if (
+					connections.main === undefined ||
+					connections.main.length === 0 ||
+					!connections.main[0]
+				) {
 					return;
 				}
 
@@ -1460,7 +1468,11 @@ export default defineComponent({
 					return;
 				}
 
-				const parentNode = connections.main[0][0].node;
+				const parentNode = connections.main[0]?.[0].node;
+				if (!parentNode) {
+					return;
+				}
+
 				const connectionsParent = this.workflowsStore.outgoingConnectionsByNodeName(parentNode);
 
 				if (!Array.isArray(connectionsParent.main) || !connectionsParent.main.length) {
@@ -1472,7 +1484,7 @@ export default defineComponent({
 				let lastCheckedNodePosition = e.key === 'ArrowUp' ? -99999999 : 99999999;
 				let nextSelectNode: string | null = null;
 				for (const ouputConnections of connectionsParent.main) {
-					for (const ouputConnection of ouputConnections) {
+					for (const ouputConnection of ouputConnections ?? []) {
 						if (ouputConnection.node === lastSelectedNode.name) {
 							// Ignore current node
 							continue;
@@ -3877,13 +3889,10 @@ export default defineComponent({
 						sourceIndex++
 					) {
 						const nodeSourceConnections = [];
-						if (currentConnections[sourceNode][type][sourceIndex]) {
-							for (
-								connectionIndex = 0;
-								connectionIndex < currentConnections[sourceNode][type][sourceIndex].length;
-								connectionIndex++
-							) {
-								connectionData = currentConnections[sourceNode][type][sourceIndex][connectionIndex];
+						const connections = currentConnections[sourceNode][type][sourceIndex];
+						if (connections) {
+							for (connectionIndex = 0; connectionIndex < connections.length; connectionIndex++) {
+								connectionData = connections[connectionIndex];
 								if (!createNodeNames.includes(connectionData.node)) {
 									// Node does not get created so skip input connection
 									continue;
@@ -4013,14 +4022,17 @@ export default defineComponent({
 				for (type of Object.keys(connections)) {
 					for (sourceIndex = 0; sourceIndex < connections[type].length; sourceIndex++) {
 						connectionToKeep = [];
-						for (
-							connectionIndex = 0;
-							connectionIndex < connections[type][sourceIndex].length;
-							connectionIndex++
-						) {
-							connectionData = connections[type][sourceIndex][connectionIndex];
-							if (exportNodeNames.indexOf(connectionData.node) !== -1) {
-								connectionToKeep.push(connectionData);
+						const connectionsToCheck = connections[type][sourceIndex];
+						if (connectionsToCheck) {
+							for (
+								connectionIndex = 0;
+								connectionIndex < connectionsToCheck.length;
+								connectionIndex++
+							) {
+								connectionData = connectionsToCheck[connectionIndex];
+								if (exportNodeNames.indexOf(connectionData.node) !== -1) {
+									connectionToKeep.push(connectionData);
+								}
 							}
 						}
 

packages/workflow/src/Interfaces.ts

@@ -364,7 +364,8 @@ export interface ICredentialDataDecryptedObject {
 
 // First array index: The output/input-index (if node has multiple inputs/outputs of the same type)
 // Second array index: The different connections (if one node is connected to multiple nodes)
-export type NodeInputConnections = IConnection[][];
+// Any index can be null, for example in a switch node with multiple indexes some of which are not connected
+export type NodeInputConnections = Array<IConnection[] | null>;
 
 export interface INodeConnection {
 	sourceIndex: number;

packages/workflow/src/Workflow.ts

@@ -194,7 +194,7 @@ export class Workflow {
 							returnConnection[connectionInfo.node][connectionInfo.type].push([]);
 						}
 
-						returnConnection[connectionInfo.node][connectionInfo.type][connectionInfo.index].push({
+						returnConnection[connectionInfo.node][connectionInfo.type][connectionInfo.index]?.push({
 							node: sourceNode,
 							type,
 							index: parseInt(inputIndex, 10),
@@ -551,18 +551,18 @@ export class Workflow {
 		let type: string;
 		let sourceIndex: string;
 		let connectionIndex: string;
-		let connectionData: IConnection;
+		let connectionData: IConnection | undefined;
 		for (sourceNode of Object.keys(this.connectionsBySourceNode)) {
 			for (type of Object.keys(this.connectionsBySourceNode[sourceNode])) {
 				for (sourceIndex of Object.keys(this.connectionsBySourceNode[sourceNode][type])) {
 					for (connectionIndex of Object.keys(
-						this.connectionsBySourceNode[sourceNode][type][parseInt(sourceIndex, 10)],
+						this.connectionsBySourceNode[sourceNode][type][parseInt(sourceIndex, 10)] || [],
 					)) {
 						connectionData =
-							this.connectionsBySourceNode[sourceNode][type][parseInt(sourceIndex, 10)][
+							this.connectionsBySourceNode[sourceNode][type][parseInt(sourceIndex, 10)]?.[
 								parseInt(connectionIndex, 10)
 							];
-						if (connectionData.node === currentName) {
+						if (connectionData?.node === currentName) {
 							connectionData.node = newName;
 						}
 					}
@@ -615,7 +615,7 @@ export class Workflow {
 		const returnNodes: string[] = [];
 		let addNodes: string[];
 
-		let connectionsByIndex: IConnection[];
+		let connectionsByIndex: IConnection[] | null;
 		for (
 			let connectionIndex = 0;
 			connectionIndex < this.connectionsByDestinationNode[nodeName][type].length;
@@ -627,7 +627,7 @@ export class Workflow {
 			}
 			connectionsByIndex = this.connectionsByDestinationNode[nodeName][type][connectionIndex];
 			// eslint-disable-next-line @typescript-eslint/no-loop-func
-			connectionsByIndex.forEach((connection) => {
+			connectionsByIndex?.forEach((connection) => {
 				if (checkedNodes.includes(connection.node)) {
 					// Node got checked already before
 					return;
@@ -742,7 +742,7 @@ export class Workflow {
 			checkedNodes.push(nodeName);
 
 			connections[nodeName][type].forEach((connectionsByIndex) => {
-				connectionsByIndex.forEach((connection) => {
+				connectionsByIndex?.forEach((connection) => {
 					if (checkedNodes.includes(connection.node)) {
 						// Node got checked already before
 						return;
@@ -839,7 +839,7 @@ export class Workflow {
 				}
 
 				connections[curr.name][type].forEach((connectionsByIndex) => {
-					connectionsByIndex.forEach((connection) => {
+					connectionsByIndex?.forEach((connection) => {
 						queue.push({
 							name: connection.node,
 							indicies: [connection.index],
@@ -943,6 +943,10 @@ export class Workflow {
 
 		let outputIndex: INodeConnection | undefined;
 		for (const connectionsByIndex of this.connectionsByDestinationNode[nodeName][type]) {
+			if (!connectionsByIndex) {
+				continue;
+			}
+
 			for (
 				let destinationIndex = 0;
 				destinationIndex < connectionsByIndex.length;

packages/workflow/test/TelemetryHelpers.test.ts

@@ -990,11 +990,8 @@ function alphanumericId() {
 
 const chooseRandomly = <T>(array: T[]) => array[randomInt(array.length)];
 
-function generateTestWorkflowAndRunData(): { workflow: IWorkflowBase; runData: IRunData } {
-	const workflow: IWorkflowBase = {
-		meta: {
-			instanceId: 'a786b722078489c1fa382391a9f3476c2784761624deb2dfb4634827256d51a0',
-		},
+function generateTestWorkflowAndRunData(): { workflow: Partial<IWorkflowBase>; runData: IRunData } {
+	const workflow: Partial<IWorkflowBase> = {
 		nodes: [
 			{
 				parameters: {},