How to use the cldr.extractFields function in cldr

extractFields: function(locale) {
    return cldr.extractFields(locale);
  }

function extractFields(locale, fieldNames) {
    assert(isValidLocale(locale), 'Invalid locale');

    var fields = cldr.extractFields(normalize(locale));

    if (fieldNames) {
        fields = fieldNames.reduce(function (filteredFields, fieldName) {
            filteredFields[fieldName] = fields[fieldName];
            return filteredFields;
        }, {});
    }

    if (!Object.keys(fields).length) {
        return null;
    }

    return fields;
}

extractFields: function(locale) {
    return cldr.extractFields(locale);
  },