fix(Transform): transform object with null prototype

Author: NoNameProvided

src/TransformOperationExecutor.ts

@@ -74,7 +74,7 @@ export class TransformOperationExecutor {
 
             return new Date(value);
 
-        } else if (value instanceof Object) {
+        } else if (typeof value === "object" && value !== null) {
 
             // try to guess the type
             if (!targetType && value.constructor !== Object/* && TransformationType === TransformationType.CLASS_TO_PLAIN*/) targetType = value.constructor;

test/functional/basic-functionality.spec.ts

@@ -1555,7 +1555,7 @@ describe("basic functionality", () => {
 
     });
 
-    it("should be able to transform array too", () => {
+    it("should transform array", () => {
         defaultMetadataStorage.clear();
 
 
@@ -1681,4 +1681,17 @@ describe("basic functionality", () => {
 
     });
 
+    it("should transform objects with null prototype", () => {
+        class TestClass {
+            prop: string;
+        }
+
+        const obj = Object.create(null);
+        obj.a = "JS FTW";
+
+        const transformedClass = plainToClass(TestClass, obj);
+
+        transformedClass.should.be.instanceOf(TestClass);
+    });
+
 });