Pure functional state management for Vuex

pfsmfv.md

• Make state immutable (in PS everything is immutable so 0 overhead for this)
• No getters, no mutations: Lens, or something similar, may work here
  • get :: forall state a. (state -> a) -> ActionT state () a
  • commit :: forall state. (state -> state) -> ActionT state () Unit
• actions :: forall state eff. ActionT state (Aff eff) Unit?

data AppState = AppState { counter :: Int }

type Action eff = ActionT AppState (Aff eff) Unit

-- guess we already have lenses for AppState

reqIncreaseCounter :: Action (http :: HTTP)
reqIncreaseCounter = do
  c <- get (_AppState..counter)
  increased <- someRequest c
  increaseCounter increased

increaseCounter :: Int -> Action ()
increaseCounter increased = do
  commit (_AppState..counter +~ increased)

Thinking about how to express computed properties.