dist/scripts/vendor.min.js
function setupValidity(instance) {
  instance.$$classCache = {};
  instance.$$classCache[INVALID_CLASS] = !(instance.$$classCache[VALID_CLASS] = instance.$$element.hasClass(VALID_CLASS));
}
function setupValidity(instance) {
  instance.$$classCache = {};
  instance.$$classCache[INVALID_CLASS] = !(instance.$$classCache[VALID_CLASS] = instance.$$element.hasClass(VALID_CLASS));
}
helper methods