fix(Execution Data Node): Set nulish values as empty string, continue on fail support (#16696)

Co-authored-by: Elias Meire <elias@meire.dev>
Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

packages/nodes-base/nodes/ExecutionData/test/ExecutionData.node.test.ts

@@ -1,6 +1,11 @@
 import { NodeTestHarness } from '@nodes-testing/node-test-harness';
 import { mock } from 'jest-mock-extended';
-import type { IExecuteFunctions, INodeExecutionData } from 'n8n-workflow';
+import type {
+	IExecuteFunctions,
+	INodeExecutionData,
+	IWorkflowDataProxyData,
+	INode,
+} from 'n8n-workflow';
 
 import { ExecutionData } from '../ExecutionData.node';
 
@@ -12,11 +17,39 @@ describe('ExecutionData Node', () => {
 		];
 		const executeFns = mock<IExecuteFunctions>({
 			getInputData: () => mockInputData,
+			getNode: () => mock<INode>({ typeVersion: 1 }),
 		});
+
 		const result = await new ExecutionData().execute.call(executeFns);
 
 		expect(result).toEqual([mockInputData]);
 	});
+
+	it('should set nullish values to empty string', async () => {
+		const mockInputData: INodeExecutionData[] = [
+			{ json: { item: 0, foo: undefined } },
+			{ json: { item: 1, foo: null } },
+			{ json: { item: 1, foo: 'bar' } },
+		];
+		const setAllMock = jest.fn();
+		const executeFns = mock<IExecuteFunctions>({
+			getInputData: () => mockInputData,
+			getWorkflowDataProxy: () =>
+				mock<IWorkflowDataProxyData>({ $execution: { customData: { setAll: setAllMock } } }),
+			getNode: () => mock<INode>({ typeVersion: 1.1 }),
+		});
+		executeFns.getNodeParameter.mockReturnValueOnce('save');
+		executeFns.getNodeParameter.mockReturnValueOnce({ values: [{ key: 'foo', value: undefined }] });
+		executeFns.getNodeParameter.mockReturnValueOnce({ values: [{ key: 'foo', value: null }] });
+		executeFns.getNodeParameter.mockReturnValueOnce({ values: [{ key: 'foo', value: 'bar' }] });
+		const result = await new ExecutionData().execute.call(executeFns);
+
+		expect(setAllMock).toBeCalledTimes(3);
+		expect(setAllMock).toBeCalledWith({ foo: '' });
+		expect(setAllMock).toBeCalledWith({ foo: '' });
+		expect(setAllMock).toBeCalledWith({ foo: 'bar' });
+		expect(result).toEqual([mockInputData]);
+	});
 });
 
 describe('ExecutionData -> Should run the workflow', () => {