diff --git a/src/index.js b/src/index.js
index dd7f003..4b866ba 100755
--- a/src/index.js
+++ b/src/index.js
@@ -7,7 +7,7 @@ export function klona(x) {
 		if (x.constructor !== Object && typeof x.constructor === 'function') {
 			tmp = new x.constructor();
 			for (k in x) {
-				if (tmp.hasOwnProperty(k) && tmp[k] !== x[k]) {
+				if (x.hasOwnProperty(k) && tmp[k] !== x[k]) {
 					tmp[k] = klona(x[k]);
 				}
 			}
diff --git a/src/lite.js b/src/lite.js
index d0ee09d..bbd342e 100644
--- a/src/lite.js
+++ b/src/lite.js
@@ -7,7 +7,7 @@ export function klona(x) {
 		if (x.constructor !== Object && typeof x.constructor === 'function') {
 			tmp = new x.constructor();
 			for (k in x) {
-				if (tmp.hasOwnProperty(k) && tmp[k] !== x[k]) {
+				if (x.hasOwnProperty(k) && tmp[k] !== x[k]) {
 					tmp[k] = klona(x[k]);
 				}
 			}
diff --git a/test/suites/class.js b/test/suites/class.js
index 5d28822..65d7475 100644
--- a/test/suites/class.js
+++ b/test/suites/class.js
@@ -203,5 +203,19 @@ export default function (klona) {
 		);
 	});
 
+	Classes('constructor properties :: Object.assign', () => {
+		class Foobar {
+			constructor(data) {
+				Object.assign(this, data);
+			}
+		}
+		const input = new Foobar({ test: 123 });
+		const output = klona(input);
+
+		assert.deepEqual(input, output);
+		assert.equal(input.constructor, output.constructor);
+		assert.equal(output.constructor.name, 'Foobar');
+	});
+
 	Classes.run();
 }