Intl.PluralRules is a new API which exposes language-dependent data on pluralization forms of numbers. Given a locale and a number, Intl.PluralRules outputs a category, which can then be used for selection of the pluralization form of surrounding text.
Docs: https://developers.google.com/web/updates/2017/10/intl-pluralrules https://tc39.github.io/ecma402/#pluralrules-objects