JSTests/test262/test/intl402/BigInt/prototype/toLocaleString/default-options-object-prototype.js

// Copyright (C) 2017 Daniel Ehrenberg. All rights reserved.
// Copyright (C) 2019 Igalia S.L. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
esid: sec-initializenumberformat
description: >
  Monkey-patching Object.prototype does not change the default
  options for NumberFormat as a null prototype is used.
info: |
  InitializeNumberFormat ( numberFormat, locales, options )

    1. If _options_ is *undefined*, then
      1. Let _options_ be ObjectCreate(*null*).
locale: [en-US]
features: [BigInt]
---*/

Object.prototype.useGrouping = false;
assert.sameValue(12345n.toLocaleString("en-US"), "12,345");