function LookupSupportedLocales(availableLocales, requestedLocales) {
        var subset = [];
        for (var _i = 0, requestedLocales_1 = requestedLocales; _i < requestedLocales_1.length; _i++) {
            var locale = requestedLocales_1[_i];
            var noExtensionLocale = locale.replace(UNICODE_EXTENSION_SEQUENCE_REGEX, '');
            var availableLocale = BestAvailableLocale(availableLocales, noExtensionLocale);
            if (availableLocale) {
                subset.push(availableLocale);
            }
        }
        return subset;
    }
https://tc39.es/ecma402/#sec-lookupsupportedlocales
@param availableLocales
@param requestedLocales