safari > 11 QuotaExceededError error in private mode

the error is raised when using localStorage in safari private mode in version prior to 11, the solution is pretty easy
wrap localStorage call in setUserOptions() with try catch:

you can read more about it here https://stackoverflow.com/questions/21159301/quotaexceedederror-dom-exception-22-an-attempt-was-made-to-add-something-to-st