fix(MongoDB Node): Stop overwriting nested values on update (#15543)

packages/nodes-base/nodes/MongoDb/GenericFunctions.test.ts

@@ -0,0 +1,80 @@
+import { prepareItems } from './GenericFunctions';
+
+describe('MongoDB Node: Generic Functions', () => {
+	describe('prepareItems', () => {
+		it('should select fields', () => {
+			const items = [{ json: { name: 'John', age: 30 } }, { json: { name: 'Jane', age: 25 } }];
+			const fields = ['name'];
+
+			const result = prepareItems({ items, fields });
+
+			expect(result).toEqual([{ name: 'John' }, { name: 'Jane' }]);
+		});
+
+		it('should add updateKey to selected fields', () => {
+			const items = [{ json: { name: 'John', age: 30 } }, { json: { name: 'Jane', age: 25 } }];
+			const fields = ['age'];
+			const updateKey = 'name';
+
+			const result = prepareItems({ items, fields, updateKey });
+
+			expect(result).toEqual([
+				{ name: 'John', age: 30 },
+				{ name: 'Jane', age: 25 },
+			]);
+		});
+
+		it('should handle dot notation', () => {
+			const items = [{ json: { user: { name: 'John' } } }, { json: { user: { name: 'Jane' } } }];
+			const fields = ['user.name'];
+			const useDotNotation = true;
+
+			const result = prepareItems({ items, fields, updateKey: '', useDotNotation });
+
+			expect(result).toEqual([{ user: { name: 'John' } }, { user: { name: 'Jane' } }]);
+		});
+
+		it('should parse dates', () => {
+			const items = [
+				{ json: { date: '2023-10-01T00:00:00Z' } },
+				{ json: { date: '2023-10-02T00:00:00Z' } },
+			];
+			const fields = ['date'];
+			const dateFields = ['date'];
+			const useDotNotation = false;
+			const isUpdate = false;
+			const result = prepareItems({
+				items,
+				fields,
+				updateKey: '',
+				useDotNotation,
+				dateFields,
+				isUpdate,
+			});
+			expect(result).toEqual([
+				{ date: new Date('2023-10-01T00:00:00Z') },
+				{ date: new Date('2023-10-02T00:00:00Z') },
+			]);
+		});
+
+		it('should handle updates', () => {
+			// Should keep dot notation in result to not overwrite the original values
+			const items = [
+				{ json: { id: 1, user: { name: 'John', age: 30 } } },
+				{ json: { id: 2, user: { name: 'Jane', age: 25 } } },
+			];
+			const fields = ['user.name'];
+			const useDotNotation = true;
+			const isUpdate = true;
+			const result = prepareItems({
+				items,
+				fields,
+				updateKey: '',
+				useDotNotation,
+				dateFields: [],
+				isUpdate,
+			});
+			expect(result).toEqual([{ 'user.name': 'John' }, { 'user.name': 'Jane' }]);
+		});
+	});
+});