From fbd2763ea61fd5842fdfc95e8c0bd204ca32e1d4 Mon Sep 17 00:00:00 2001
From: Madeorsk <m@deor.sk>
Date: Sun, 20 Apr 2025 20:30:27 +0200
Subject: [PATCH] Add assign function to assign properties values using any
 object, silently ignoring fields which are not properties.

---
 README.md           | 12 ++++++++++++
 src/model/model.ts  | 16 ++++++++++++++++
 tests/model.test.ts | 30 ++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+)

diff --git a/README.md b/README.md
index b17d147..4bd104e 100644
--- a/README.md
+++ b/README.md
@@ -274,6 +274,18 @@ Get a model class (which has all the sharkitek models' functions) from a model i
 const model = definedModel.model(modelInstance);
 ```
 
+#### `assign(object)`
+
+Assign fields from a provided object to the model instance properties. Fields which are not properties of the target model are silently ignored.
+
+```typescript
+const alteredModelInstance = definedModel.model(modelInstance).assign({
+	anyProperty: "foo",
+	anotherOne: true,
+	not_a_property: "will be ignored",
+});
+```
+
 #### `serialize()`
 
 Serialize the model.
diff --git a/src/model/model.ts b/src/model/model.ts
index 618ad48..c676e46 100644
--- a/src/model/model.ts
+++ b/src/model/model.ts
@@ -382,6 +382,22 @@ export class Model<T extends object, Shape extends ModelShape<T>, Identifier ext
 
 		return cloned.instance; // Returning the cloned instance.
 	}
+
+	/**
+	 * Assign the provided fields to existing properties.
+	 * Fields that cannot be matched to existing properties are silently ignored.
+	 * @param fields The fields to assign to the model.
+	 */
+	assign(fields: Partial<ModelPropertiesValues<T, Shape>> & {[field: string]: any}): ModelInstance<T, Shape, Identifier>
+	{
+		for (const field in fields)
+		{ // For each field, if it's a property, assign its value.
+			if ((this.definition.properties as any)?.[field])
+				// Set the instance value.
+				this.instance[field as keyof T] = fields[field];
+		}
+		return this.instance;
+	}
 }
 
 
diff --git a/tests/model.test.ts b/tests/model.test.ts
index d6c8393..ef3f34b 100644
--- a/tests/model.test.ts
+++ b/tests/model.test.ts
@@ -326,4 +326,34 @@ describe("model", () => {
 		expect(TestModel.model.model(clonedDeserializedModel).serialize()).toStrictEqual({ id: 5, label: "testing" });
 		expect(clonedDeserializedModel.notAProperty.hello).toEqual("world");
 	});
+
+	it("assigns properties, ignoring fields which are not properties", () => {
+		const deserializedArticle = Article.model.parse({
+			id: 1,
+			title: "this is a test",
+			authors: [
+				{ id: 52, name: "John Doe", email: "test@test.test", createdAt: "2022-08-07T08:47:01.000Z", active: true, },
+				{ id: 4, name: "Tester", email: "another@test.test", createdAt: "2022-09-07T18:32:55.000Z", active: false, },
+			],
+			text: "this is a long test.",
+			evaluation: "8.52",
+			tags: [ {name: "test"}, {name: "foo"} ],
+			comments: [
+				{ id: 542, author: { id: 52, name: "John Doe", email: "test@test.test", createdAt: "2022-08-07T08:47:01.000Z", active: true, }, message: "comment content", },
+			],
+		});
+
+		// Assign title and text, html is silently ignored.
+		Article.model.model(deserializedArticle).assign({
+			title: "something else",
+			text: "fully new text! yes!",
+			html: "<p>fully new text! yes!</p>",
+		});
+		expect((deserializedArticle as any)?.html).toBeUndefined();
+		expect(Article.model.model(deserializedArticle).patch()).toStrictEqual({
+			id: 1,
+			title: "something else",
+			text: "fully new text! yes!",
+		});
+	});
 });