One of the most crucial features of apps today is data persistence. If you don’t quite understand why, a fundamental definition of the concept will help. Data persistence refers to the mechanism of storage of data, irrelevant of its type, to a disk. The point is to make sure that this data can then be retrieved later whenever users open the app and allow them to continue from precisely where they left off.
This guide, however, will focus on techniques and methods exclusively in the context of storing data locally in an iOS app. And before we get started with that, it is essential to understand that local storage in iOS apps is not the default setting. Instead, what happens is that all the constants and variables assigned in Swift are stored in memory by default.