This question statement often comes up.
We’re developing an iOS application, and of course, the user would have to input some personal information before he/she can start using the application. What kind of validations should be implement on the device? Which ones on the server?
Most people, especially when starting out on a new project, consider input validation to be a fairly trivial problem statement with fixed states. But, as the application matures, they fairly quickly realize that every input has its own set of error and valid states. The validation problem …