From ed3f8cc39df9742ac56937d786eecdc03d723668 Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Sun, 3 Jan 2016 18:49:32 -0600
Subject: [PATCH] Add support for creating clones with the same `[[Prototype]]`
 as `value`.

---
 lodash.js    | 15 +++++++--------
 test/test.js |  8 +++++++-
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/lodash.js b/lodash.js
index fdae8dfbf..ff3f722b9 100644
--- a/lodash.js
+++ b/lodash.js
@@ -2272,7 +2272,7 @@
      * @returns {Function} Returns the new function.
      */
     function baseConforms(source) {
-      var props = keysIn(source),
+      var props = keys(source),
           length = props.length;
 
       return function(object) {
@@ -4834,7 +4834,7 @@
      */
     function initCloneArray(array) {
       var length = array.length,
-          result = new array.constructor(length);
+          result = array.constructor(length);
 
       // Add properties assigned by `RegExp#exec`.
       if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {
@@ -4853,7 +4853,7 @@
      */
     function initCloneObject(object) {
       var Ctor = object.constructor;
-      return (typeof Ctor == 'function' && Ctor instanceof Ctor) ? new Ctor : {};
+      return baseCreate(isFunction(Ctor) ? Ctor.prototype : undefined);
     }
 
     /**
@@ -9066,11 +9066,10 @@
      * **Note:** This method is loosely based on the
      * [structured clone algorithm](https://mdn.io/Structured_clone_algorithm)
      * and supports cloning arrays, array buffers, booleans, date objects, maps,
-     * numbers, `Object` objects, regexes, sets, strings, symbols, and typed arrays.
-     * The own enumerable properties of `arguments` objects and objects created
-     * by constructors other than `Object` are cloned as plain `Object` objects.
-     * An empty object is returned for uncloneable values such as error objects,
-     * functions, DOM nodes, and WeakMaps.
+     * numbers, `Object` objects, regexes, sets, strings, symbols, and typed
+     * arrays. The own enumerable properties of `arguments` objects are cloned
+     * as plain objects. An empty object is returned for uncloneable values such
+     * as error objects, functions, DOM nodes, and WeakMaps.
      *
      * @static
      * @memberOf _
diff --git a/test/test.js b/test/test.js
index 336c92e9f..39bbc4512 100644
--- a/test/test.js
+++ b/test/test.js
@@ -2263,7 +2263,7 @@
 
   (function() {
     function Foo() { this.a = 1; }
-    Foo.prototype = { 'b': 1 };
+    Foo.prototype.b = 1;
     Foo.c = function() {};
 
     if (Map) {
@@ -2451,6 +2451,12 @@
         assert.strictEqual(actual.lastIndex, 3);
       });
 
+      QUnit.test('`_.' + methodName + '` should create clone with the same `[[Prototype]]` as `value`', function(assert) {
+        assert.expect(1);
+
+        assert.ok(func(new Foo) instanceof Foo);
+      });
+
       QUnit.test('`_.' + methodName + '` should clone properties that shadow those on `Object.prototype`', function(assert) {
         assert.expect(2);