> Parent is simply referring to the front-end skill of building an app with rich client-side state that isn't persisted to a backend DB.
Frequently some or all of the state is persisted to a datastore, whether client-side or backend (which of those isn't really a substantive difference in the skill involved, except that backend stores make planning around communication failures more important), and even when it's not, “my internal data structures don't also get loaded from and saved to an external store” doesn’t add any additional required skill, it strictly reduces the set of skills that need to be applied.
Frequently some or all of the state is persisted to a datastore, whether client-side or backend (which of those isn't really a substantive difference in the skill involved, except that backend stores make planning around communication failures more important), and even when it's not, “my internal data structures don't also get loaded from and saved to an external store” doesn’t add any additional required skill, it strictly reduces the set of skills that need to be applied.