@formatjs/intl-relativetimeformat/lib/polyfill.js

import RelativeTimeFormat from './';
import { shouldPolyfill } from './should-polyfill';
if (shouldPolyfill()) {
    Object.defineProperty(Intl, 'RelativeTimeFormat', {
        value: RelativeTimeFormat,
        writable: true,
        enumerable: false,
        configurable: true,
    });
}