Bug: Cannot read property 'prototype' of undefined error

[StCyr]

Description

In a react-native expo iOS app, after upgrading i18n-js to version 4+ (tested with 4.4.3, 4.4.2, and 4.0.0), I get a "Cannot read property 'prototype' of undefined" error when I try to instantiate a new I18n class.

This error has been reported here but I could only fix it by downgrading to version 3.8.0

How to reproduce

Here's the code that triggers this issue:

import * as Localization from 'expo-localization';
import I18n from 'i18n-js';
import { en, fr, ru, ua, ca, de, it, sv, pl } from './languages';

const i18n = new I18n({ en, fr, ru, ua, ca, de, it, sv, pl });

i18n.fallbacks = true;
i18n.defaultLocale = 'en';
i18n.locale = Localization.locale;

export {i18n};

What do you expect

const i18n instantiated properly

What happened instead

"Cannot read property 'prototype' of undefined error"

Full backtrace

Here's a screenshot of the stacktrace: