I don't think bundling of state and action is inherently an antipattern (even in functional programming there is an implicit coupling between the shape of the a

I don't think bundling of state and action is inherently an antipattern (even in functional programming there is an implicit coupling between the shape of the app state and functions that operate on the app state), but in a system with countless individual units of tightly coupled state and actions interacting with eachother, it's all too easy to fall into the real antipattern of overusing in-place state mutations and neglecting deliberate management of state transitions across the entire system. Functional approaches to frontend development tend to encourage patterns like the single immutable app state tree and writing state transitions as pure functions, which helps minimize this source of complexity.