Polyfill Array copying methods

Summary:
Install guarded `Array.prototype.toSorted` and `Array.prototype.toReversed` polyfills during core environment setup. Both methods return shallow copies and preserve native implementations when the runtime already provides them.

Changelog:
[General][Added] - Polyfill `Array.prototype.toSorted` and `Array.prototype.toReversed` when the JavaScript runtime does not provide them

Differential Revision: D125283374

Author: javache

packages/react-native/Libraries/Core/__tests__/setUpArrayES2023Methods-test.js

@@ -0,0 +1,101 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict
+ * @format
+ */
+
+'use strict';
+
+const arrayPrototype = Array.prototype;
+const toSortedProperty: string = 'toSorted';
+const toReversedProperty: string = 'toReversed';
+const originalToSorted = Object.getOwnPropertyDescriptor(
+  arrayPrototype,
+  toSortedProperty,
+);
+const originalToReversed = Object.getOwnPropertyDescriptor(
+  arrayPrototype,
+  toReversedProperty,
+);
+
+function removeCopyingMethods(): void {
+  Object.defineProperty(arrayPrototype, toSortedProperty, {
+    configurable: true,
+    value: undefined,
+    writable: true,
+  });
+  Object.defineProperty(arrayPrototype, toReversedProperty, {
+    configurable: true,
+    value: undefined,
+    writable: true,
+  });
+}
+
+function restoreCopyingMethods(): void {
+  if (originalToSorted == null) {
+    Reflect.deleteProperty(arrayPrototype, toSortedProperty);
+  } else {
+    Object.defineProperty(arrayPrototype, toSortedProperty, originalToSorted);
+  }
+  if (originalToReversed == null) {
+    Reflect.deleteProperty(arrayPrototype, toReversedProperty);
+  } else {
+    Object.defineProperty(
+      arrayPrototype,
+      toReversedProperty,
+      originalToReversed,
+    );
+  }
+}
+
+describe('setUpArrayES2023Methods', () => {
+  beforeEach(() => {
+    jest.resetModules();
+    removeCopyingMethods();
+  });
+
+  afterEach(() => {
+    restoreCopyingMethods();
+  });
+
+  test('installs non-mutating copying methods', () => {
+    require('../setUpArrayES2023Methods');
+
+    const input = [3, 1, 2];
+    expect(input.toSorted((a, b) => a - b)).toEqual([1, 2, 3]);
+    expect(input.toReversed()).toEqual([2, 1, 3]);
+    expect(input).toEqual([3, 1, 2]);
+    expect(
+      Object.getOwnPropertyDescriptor(arrayPrototype, toSortedProperty)
+        ?.enumerable,
+    ).toBe(false);
+    expect(
+      Object.getOwnPropertyDescriptor(arrayPrototype, toReversedProperty)
+        ?.enumerable,
+    ).toBe(false);
+  });
+
+  test('preserves native implementations', () => {
+    const nativeToSorted = jest.fn(() => ['sorted']);
+    const nativeToReversed = jest.fn(() => ['reversed']);
+    Object.defineProperty(arrayPrototype, toSortedProperty, {
+      configurable: true,
+      value: nativeToSorted,
+      writable: true,
+    });
+    Object.defineProperty(arrayPrototype, toReversedProperty, {
+      configurable: true,
+      value: nativeToReversed,
+      writable: true,
+    });
+
+    require('../setUpArrayES2023Methods');
+
+    expect(arrayPrototype.toSorted).toBe(nativeToSorted);
+    expect(arrayPrototype.toReversed).toBe(nativeToReversed);
+  });
+});

packages/react-native/Libraries/Core/setUpArrayES2023Methods.js

@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict
+ * @format
+ */
+
+'use strict';
+
+const arrayPrototype = Array.prototype;
+
+if (arrayPrototype.toSorted == null) {
+  const toSortedProperty: string = 'toSorted';
+  Object.defineProperty(arrayPrototype, toSortedProperty, {
+    configurable: true,
+    value: function <T>(
+      this: Array<T>,
+      compareFn?: (a: T, b: T) => number,
+    ): Array<T> {
+      const copy = Array.from(this);
+      copy.sort(compareFn);
+      return copy;
+    },
+    writable: true,
+  });
+}
+
+if (arrayPrototype.toReversed == null) {
+  const toReversedProperty: string = 'toReversed';
+  Object.defineProperty(arrayPrototype, toReversedProperty, {
+    configurable: true,
+    value: function <T>(this: Array<T>): Array<T> {
+      const copy = Array.from(this);
+      copy.reverse();
+      return copy;
+    },
+    writable: true,
+  });
+}

packages/react-native/Libraries/Core/setUpGlobals.js

@@ -11,6 +11,8 @@
 'use client';
 'use strict';
 
+import './setUpArrayES2023Methods';
+
 /**
  * Sets up global variables for React Native.
  * You can use this module directly, or just require InitializeCore.