getLocaleDateFormatter = (locale, timeUnit='day') => {
        let options = localeTimeMap[timeUnit];
        let formatter = new Intl.DateTimeFormat(locale, options);

        return (date) => formatter.format(date);
    }
Takes a locale (string) and the format to return and returns a function to format dates
@param  {String} locale              Locale tag eg. en-US, fr-FR, ru-RU
@param  {String} [timeUnit='day']    Minute, hour, day, dayMonth, month, year
@return {Function}                   Function that formats dates in the proper locale