🔀 Merge branch 'TMaYaD-merge-overwrite'

packages/nodes-base/nodes/Merge.node.ts

@@ -164,6 +164,37 @@ export class Merge implements INodeType {
 				default: 'input1',
 				description: 'Defines of which input the data should be used as output of node.',
 			},
+			{
+				displayName: 'Overwrite',
+				name: 'overwrite',
+				type: 'options',
+				displayOptions: {
+					show: {
+						mode: [
+							'mergeByKey',
+						],
+					},
+				},
+				options: [
+					{
+						name: 'Always',
+						value: 'always',
+						description: 'Always overwrites everything.',
+					},
+					{
+						name: 'If Blank',
+						value: 'blank',
+						description: 'Overwrites only values of "null", "undefined" or empty string.',
+					},
+					{
+						name: 'If Missing',
+						value: 'undefined',
+						description: 'Only adds values which do not exist yet.',
+					},
+				],
+				default: 'always',
+				description: 'Select when to overwrite the values from Input1 with values from Input 2.',
+			}
 		]
 	};
 
@@ -285,6 +316,7 @@ export class Merge implements INodeType {
 
 			const propertyName1 = this.getNodeParameter('propertyName1', 0) as string;
 			const propertyName2 = this.getNodeParameter('propertyName2', 0) as string;
+			const overwrite = this.getNodeParameter('overwrite', 0) as string;
 
 			const dataInput2 = this.getInputData(1);
 			if (!dataInput2 || !propertyName1 || !propertyName2) {
@@ -375,8 +407,19 @@ export class Merge implements INodeType {
 						entry = JSON.parse(JSON.stringify(entry));
 
 						for (key of Object.keys(copyData[referenceValue as string].json)) {
+							if (key === propertyName2) {
+								continue;
+							}
+
 							// TODO: Currently only copies json data and no binary one
-							entry.json[key] = copyData[referenceValue as string].json[key];
+							const value = copyData[referenceValue as string].json[key];
+							if (
+								overwrite === 'always' ||
+								(overwrite === 'undefined' && !entry.json.hasOwnProperty(key)) ||
+								(overwrite === 'blank' && [null, undefined, ''].includes(entry.json[key] as string))
+							) {
+								entry.json[key] = value;
+							}
 						}
 					} else {
 						// For "keepKeyMatches" we add it as it is