From c39b16134a6a9704be2e661b49b92e8561f10d90 Mon Sep 17 00:00:00 2001
From: Brian Woodward <brian.woodward@gmail.com>
Date: Mon, 4 Jan 2021 14:30:09 -0500
Subject: [PATCH] add test to ensure constructor is not cloned

---
 test.js | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/test.js b/test.js
index 926bbae..712fbe1 100644
--- a/test.js
+++ b/test.js
@@ -134,4 +134,16 @@ describe('mergeDeep', function() {
     var actual = merge(fixture);
     assert.deepEqual(actual, fixture);
   });
+
+  it('should not clone invalid keys', function() {
+    var obj1 = { a: { b: 1 } };
+    var obj2 = JSON.parse('{ "a": { "c": 2 }, "constructor": { "keys": 42 } }');
+
+    var actual = merge({}, obj1, obj2);
+    assert.deepEqual(actual, { a: { b: 1, c: 2 } });
+    assert.notDeepEqual(actual.a, obj1.a);
+    assert.notDeepEqual(actual.a, obj2.a);
+    assert.notEqual(actual.keys, 42);
+    assert.notEqual(actual.constructor.keys, 42);
+  });
 });