From 5bffe4366a14310504894dd32bab482ef584f457 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20Lyngs=C3=B8?= <niels.lyngso@gmail.com>
Date: Wed, 24 Apr 2024 21:21:11 +0200
Subject: [PATCH] deep merge

---
 .../src/packages/core/utils/index.ts          |  3 +-
 .../core/utils/object/deep-merge.function.ts  | 22 +++++++
 .../core/utils/object/deep-merge.test.ts      | 61 +++++++++++++++++++
 3 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 src/Umbraco.Web.UI.Client/src/packages/core/utils/object/deep-merge.function.ts
 create mode 100644 src/Umbraco.Web.UI.Client/src/packages/core/utils/object/deep-merge.test.ts

diff --git a/src/Umbraco.Web.UI.Client/src/packages/core/utils/index.ts b/src/Umbraco.Web.UI.Client/src/packages/core/utils/index.ts
index 8b243bcb6c..09d60ef911 100644
--- a/src/Umbraco.Web.UI.Client/src/packages/core/utils/index.ts
+++ b/src/Umbraco.Web.UI.Client/src/packages/core/utils/index.ts
@@ -16,4 +16,5 @@ export * from './string/generate-umbraco-alias.function.js';
 export * from './string/increment-string.function.js';
 export * from './string/split-string-to-array.js';
 export * from './string/to-camel-case/to-camel-case.function.js';
-export * from './type/diff.type.js';
+export type * from './type/deep-partial.type.js';
+export type * from './type/diff.type.js';
diff --git a/src/Umbraco.Web.UI.Client/src/packages/core/utils/object/deep-merge.function.ts b/src/Umbraco.Web.UI.Client/src/packages/core/utils/object/deep-merge.function.ts
new file mode 100644
index 0000000000..b08629cb1d
--- /dev/null
+++ b/src/Umbraco.Web.UI.Client/src/packages/core/utils/object/deep-merge.function.ts
@@ -0,0 +1,22 @@
+import type { DeepPartial } from '../type/deep-partial.type.js';
+
+/**
+ * Deep merge two objects.
+ * @param target
+ * @param ...sources
+ */
+export function umbDeepMerge<T extends { [key: string]: any }>(source: DeepPartial<T>, fallback: T) {
+	const result = { ...fallback };
+
+	for (const key in source) {
+		if (Object.prototype.hasOwnProperty.call(source, key) && source[key] !== undefined) {
+			if (source[key].constructor === Object && fallback[key].constructor === Object) {
+				result[key] = umbDeepMerge(source[key], fallback[key]);
+			} else {
+				result[key] = source[key] as any;
+			}
+		}
+	}
+
+	return result;
+}
diff --git a/src/Umbraco.Web.UI.Client/src/packages/core/utils/object/deep-merge.test.ts b/src/Umbraco.Web.UI.Client/src/packages/core/utils/object/deep-merge.test.ts
new file mode 100644
index 0000000000..61509c9162
--- /dev/null
+++ b/src/Umbraco.Web.UI.Client/src/packages/core/utils/object/deep-merge.test.ts
@@ -0,0 +1,61 @@
+import { expect } from '@open-wc/testing';
+import { umbDeepMerge } from './deep-merge.function.js';
+
+describe('UmbDeepMerge', () => {
+	beforeEach(() => {});
+
+	describe('merge just objects', () => {
+		it('transfers defined properties', () => {
+			const defaults = {
+				prop1: {
+					name: 'prop1',
+					value: 'value1',
+				},
+				prop2: {
+					name: 'prop2',
+					value: 'value2',
+				},
+			};
+			const source = {
+				prop2: {
+					name: 'prop2_updatedName',
+				},
+			};
+			const result = umbDeepMerge(source, defaults);
+
+			expect(result.prop1.name).to.equal('prop1');
+			expect(result.prop2.name).to.equal('prop2_updatedName');
+		});
+	});
+
+	describe('merge objects with arrays', () => {
+		// The arrays should not be merged, but take the value from the main object. [NL]
+		it('transfers defined properties', () => {
+			const defaults = {
+				prop1: {
+					name: 'prop1',
+					value: ['entry1', 'entry2', 'entry3'],
+				},
+				prop2: {
+					name: 'prop2',
+					value: ['entry4', 'entry4', 'entry5'],
+				},
+			};
+			const source = {
+				prop1: {
+					name: 'prop1_updatedName',
+				},
+				prop2: {
+					name: 'prop2_updatedName',
+					value: ['entry666'],
+				},
+			};
+			const result = umbDeepMerge(source, defaults);
+
+			expect(result.prop1.name).to.equal('prop1_updatedName');
+			expect(result.prop2.value.join(',')).to.equal(defaults.prop1.value.join(','));
+			expect(result.prop2.name).to.equal('prop2_updatedName');
+			expect(result.prop2.value.join(',')).to.equal(source.prop2.value.join(','));
+		});
+	});
+});