pass prototype through for clean clones, for faster object copying

__tests__/utils.ts

@@ -57,7 +57,7 @@ describe('getCleanClone', () => {
   it('will return a pure object when there is no constructor', () => {
     const object = Object.create(null);
 
-    const result = utils.getCleanClone(object);
+    const result = utils.getCleanClone(object, Object.getPrototypeOf(object));
 
     expect(result).not.toBe(object);
     expect(result).toEqual(object);
@@ -70,7 +70,7 @@ describe('getCleanClone', () => {
 
     object.__proto__ = null;
 
-    const result = utils.getCleanClone(object);
+    const result = utils.getCleanClone(object, Object.getPrototypeOf(object));
 
     expect(result).not.toBe(object);
     expect(result).toEqual(object);
@@ -81,22 +81,22 @@ describe('getCleanClone', () => {
   it('will return an empty POJO when the object passed is a POJO', () => {
     const object = { foo: 'bar' };
 
-    const result = utils.getCleanClone(object);
+    const result = utils.getCleanClone(object, Object.getPrototypeOf(object));
 
     expect(result).not.toBe(object);
     expect(result).toEqual({});
 
     expect(Object.getPrototypeOf(result)).toBe(Object.prototype);
   });
 
-  it('will return an empty object with custom protype when the object created through Object.create()', () => {
+  it('will return an empty object with custom prototype when the object created through Object.create()', () => {
     const object = Object.create({
       method() {},
     });
 
     object.foo = 'bar';
 
-    const result = utils.getCleanClone(object);
+    const result = utils.getCleanClone(object, Object.getPrototypeOf(object));
 
     expect(result).not.toBe(object);
     expect(result).toEqual({});
@@ -107,7 +107,7 @@ describe('getCleanClone', () => {
   it('will return an empty object with the given constructor when it is a global constructor', () => {
     const object = new Map();
 
-    const result = utils.getCleanClone(object);
+    const result = utils.getCleanClone(object, Object.getPrototypeOf(object));
 
     expect(result).not.toBe(object);
     expect(result).toEqual(new Map());
@@ -128,7 +128,7 @@ describe('getCleanClone', () => {
 
     const object = new Foo('bar');
 
-    const result = utils.getCleanClone(object);
+    const result = utils.getCleanClone(object, Object.getPrototypeOf(object));
 
     expect(result).not.toBe(object);
     expect(result).toEqual(Object.create(Foo.prototype));
@@ -155,7 +155,12 @@ describe('getObjectCloneLoose', () => {
     const handleCopy = jest.fn().mockImplementation((arg) => arg);
     const cache = utils.createCache();
 
-    const result = utils.getObjectCloneLoose(object, handleCopy, cache);
+    const result = utils.getObjectCloneLoose(
+      object,
+      Object.getPrototypeOf(object),
+      handleCopy,
+      cache
+    );
 
     Object.getOwnPropertySymbols = original;
 
@@ -179,7 +184,12 @@ describe('getObjectCloneLoose', () => {
     const handleCopy = jest.fn().mockImplementation((arg) => arg);
     const cache = utils.createCache();
 
-    const result = utils.getObjectCloneLoose(object, handleCopy, cache);
+    const result = utils.getObjectCloneLoose(
+      object,
+      Object.getPrototypeOf(object),
+      handleCopy,
+      cache
+    );
 
     expect(result).not.toBe(object);
     expect(result).toEqual(object);
@@ -215,7 +225,12 @@ describe('getObjectCloneStrict', () => {
     const handleCopy = jest.fn().mockImplementation((arg) => arg);
     const cache = utils.createCache();
 
-    const result = utils.getObjectCloneStrict(object, handleCopy, cache);
+    const result = utils.getObjectCloneStrict(
+      object,
+      Object.getPrototypeOf(object),
+      handleCopy,
+      cache
+    );
 
     Object.getOwnPropertySymbols = original;
 
@@ -253,7 +268,12 @@ describe('getObjectCloneStrict', () => {
     const handleCopy = jest.fn().mockImplementation((arg) => arg);
     const cache = utils.createCache();
 
-    const result = utils.getObjectCloneStrict(object, handleCopy, cache);
+    const result = utils.getObjectCloneStrict(
+      object,
+      Object.getPrototypeOf(object),
+      handleCopy,
+      cache
+    );
 
     expect(result).not.toBe(object);
     expect(result).toEqual(object);

src/index.ts

@@ -54,12 +54,12 @@ function performCopy<Value>(
 
     // plain objects
     if (!Constructor || Constructor === Object) {
-      return getObjectClone(value, handleCopy, cache);
+      return getObjectClone(value, prototype, handleCopy, cache);
     }
 
     // arrays
     if (isArray(value)) {
-      return getArrayClone(value, handleCopy, cache);
+      return getArrayClone(value, prototype, handleCopy, cache);
     }
 
     const objectClass = toString.call(value);
@@ -133,7 +133,7 @@ function performCopy<Value>(
     }
 
     // assume anything left is a custom constructor
-    return getObjectClone(value, handleCopy, cache);
+    return getObjectClone(value, prototype, handleCopy, cache);
   }
 
   return handleCopy(value, createCache());

src/utils.ts

@@ -55,10 +55,11 @@ export const createCache =
 
 export function getArrayCloneLoose(
   array: any[],
+  prototype: any,
   handleCopy: InternalCopier,
   cache: Cache
 ) {
-  const clone = new (array.constructor as any)();
+  const clone = new prototype.constructor();
 
   cache.set(array, clone);
 
@@ -72,9 +73,7 @@ export function getArrayCloneLoose(
 /**
  * Get an empty version of the object with the same prototype it has.
  */
-export function getCleanClone(object: any): any {
-  const prototype = object.__proto__ || getPrototypeOf(object);
-
+export function getCleanClone(object: any, prototype: any): any {
   if (!prototype) {
     return create(null);
   }
@@ -100,10 +99,11 @@ export function getCleanClone(object: any): any {
  */
 export function getObjectCloneLoose(
   object: any,
+  prototype: any,
   handleCopy: InternalCopier,
   cache: Cache
 ): any {
-  const clone: any = getCleanClone(object);
+  const clone: any = getCleanClone(object, prototype);
 
   // set in the cache immediately to be able to reuse the object recursively
   cache.set(object, clone);
@@ -149,10 +149,11 @@ const getStrictProperties = SYMBOL_PROPERTIES
  */
 export function getObjectCloneStrict(
   object: any,
+  prototype: any,
   handleCopy: InternalCopier,
   cache: Cache
 ): any {
-  const clone: any = getCleanClone(object);
+  const clone: any = getCleanClone(object, prototype);
 
   // set in the cache immediately to be able to reuse the object recursively
   cache.set(object, clone);