When we say that SwiftUI is data driven, this is not to say that it is no longer necessary to handle events generated by the user (in other words the interaction between the user and the app user interface). It is still necessary, for example, to know when the user taps a button and to react in some app specific way. Being data driven relates more to the relationship between the underlying app data and the user interface and logic of the app.
Prior to the introduction of SwiftUI, an iOS app would contain code responsible for checking the current values of data within the app. If data is likely to change over time, code has to be written to ensure that the user interface always reflects the latest state of the data (perhaps by writing code to frequently check for changes to the data, or by providing a refresh option for the user to request a data update). Similar problems arise when keeping the user interface state consistent and making sure issues like...
