A polyfill to add support for Number.toLocaleString with locales to browsers that don't support it.polyfill-Number.toLocaleString-with-Locales
Published on NPM at number-to-locale-string
A polyfill to allow locales to be passed to Number.toLocaleString.
I realize this is nowhere near complete, but it has all the locales I'm likely to use before it gets implemented across, at least, the modern browsers.
Always happy to accept pull requests from those that want to add support for more regions.