fix(editor): Fixes the issue that Switch Node can not be created (#7516)

Fixes the issue that currently no Switch-Node can be created by for
example pressing + on the parent node or via tab when another node is
already selected.

Github issue / Community forum post (link here to close automatically):

---------

Signed-off-by: Oleg Ivaniv <me@olegivaniv.com>
Co-authored-by: Oleg Ivaniv <me@olegivaniv.com>

cypress/e2e/12-canvas.cy.ts

@@ -30,6 +30,7 @@ describe('Canvas Node Manipulation and Navigation', () => {
 
 	it('should add switch node and test connections', () => {
 		const desiredOutputs = 4;
+		WorkflowPage.actions.addNodeToCanvas(MANUAL_TRIGGER_NODE_NAME, true);
 		WorkflowPage.actions.addNodeToCanvas(SWITCH_NODE_NAME, true, true);
 
 		for (let i = 0; i < desiredOutputs; i++) {
@@ -43,9 +44,14 @@ describe('Canvas Node Manipulation and Navigation', () => {
 			WorkflowPage.actions.addNodeToCanvas(EDIT_FIELDS_SET_NODE_NAME, false);
 			WorkflowPage.actions.zoomToFit();
 		}
+		WorkflowPage.getters.nodeViewBackground().click({ force: true });
+		WorkflowPage.getters.canvasNodePlusEndpointByName(`${EDIT_FIELDS_SET_NODE_NAME}3`).click();
+		WorkflowPage.actions.addNodeToCanvas(SWITCH_NODE_NAME, false);
 		WorkflowPage.actions.saveWorkflowOnButtonClick();
 		cy.reload();
 		cy.waitForLoad();
+		// Make sure outputless switch was connected correctly
+		cy.get(`[data-target-node="${SWITCH_NODE_NAME}1"][data-source-node="${EDIT_FIELDS_SET_NODE_NAME}3"]`).should('be.visible');
 		// Make sure all connections are there after reload
 		for (let i = 0; i < desiredOutputs; i++) {
 			const setName = `${EDIT_FIELDS_SET_NODE_NAME}${i > 0 ? i : ''}`;

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

@@ -265,6 +265,7 @@ import type {
 	IWorkflowBase,
 	Workflow,
 	ConnectionTypes,
+	INodeOutputConfiguration,
 } from 'n8n-workflow';
 import {
 	deepCopy,
@@ -1970,37 +1971,58 @@ export default defineComponent({
 					this.canvasStore.newNodeInsertPosition = null;
 				} else {
 					let yOffset = 0;
+					const workflow = this.getCurrentWorkflow();
 
 					if (lastSelectedConnection) {
 						const sourceNodeType = this.nodeTypesStore.getNodeType(
 							lastSelectedNode.type,
 							lastSelectedNode.typeVersion,
 						);
-						const offsets = [
-							[-100, 100],
-							[-140, 0, 140],
-							[-240, -100, 100, 240],
-						];
-						if (sourceNodeType && sourceNodeType.outputs.length > 1) {
-							const offset = offsets[sourceNodeType.outputs.length - 2];
-							const sourceOutputIndex = lastSelectedConnection.__meta
-								? lastSelectedConnection.__meta.sourceOutputIndex
-								: 0;
-							yOffset = offset[sourceOutputIndex];
+						if (sourceNodeType) {
+							const offsets = [
+								[-100, 100],
+								[-140, 0, 140],
+								[-240, -100, 100, 240],
+							];
+							const sourceNodeOutputs = NodeHelpers.getNodeOutputs(
+								workflow,
+								lastSelectedNode!,
+								sourceNodeType,
+							);
+							const sourceNodeOutputTypes = NodeHelpers.getConnectionTypes(sourceNodeOutputs);
+							const sourceNodeOutputMainOutputs = sourceNodeOutputTypes.filter(
+								(output) => output === NodeConnectionType.Main,
+							);
+							if (sourceNodeOutputMainOutputs.length > 1) {
+								const offset = offsets[sourceNodeOutputMainOutputs.length - 2];
+								const sourceOutputIndex = lastSelectedConnection.__meta
+									? lastSelectedConnection.__meta.sourceOutputIndex
+									: 0;
+								yOffset = offset[sourceOutputIndex];
+							}
 						}
 					}
 
-					const workflow = this.getCurrentWorkflow();
-					const workflowNode = workflow.getNode(newNodeData.name);
-					const outputs = NodeHelpers.getNodeOutputs(workflow, workflowNode!, nodeTypeData);
+					let outputs: Array<ConnectionTypes | INodeOutputConfiguration> = [];
+					try {
+						// It fails when the outputs are an expression. As those node have
+						// normally no outputs by default and the only reason we need the
+						// outputs here is to calculate the position it is fine to assume
+						// that they have no outputs and are so treated as a regular node
+						// with only "main" outputs.
+						outputs = NodeHelpers.getNodeOutputs(workflow, newNodeData!, nodeTypeData);
+					} catch (e) {}
 					const outputTypes = NodeHelpers.getConnectionTypes(outputs);
 					const lastSelectedNodeType = this.nodeTypesStore.getNodeType(
 						lastSelectedNode.type,
 						lastSelectedNode.typeVersion,
 					);
 
 					// If node has only scoped outputs, position it below the last selected node
-					if (outputTypes.every((outputName) => outputName !== NodeConnectionType.Main)) {
+					if (
+						outputTypes.length > 0 &&
+						outputTypes.every((outputName) => outputName !== NodeConnectionType.Main)
+					) {
 						const lastSelectedNodeWorkflow = workflow.getNode(lastSelectedNode.name);
 						const lastSelectedInputs = NodeHelpers.getNodeInputs(
 							workflow,
@@ -2025,6 +2047,7 @@ export default defineComponent({
 							[100, 0],
 						);
 					} else {
+						// Has only main outputs or no outputs at all
 						const inputs = NodeHelpers.getNodeInputs(
 							workflow,
 							lastSelectedNode,