Store

final public class Store

Store that contains the application state, the reducer logic, the middleware and the listeners

The store contains four components:

  • state: represents the application state. This state is partitioned into state keys. Each key can represents a full application screen, flow, or view controller.
  • reducer represents the logic to update the state. A reducer mainly provides a function that updates the state for a paticular action.
  • middleware: an object (or list of objects) that intercept an action and can enrich or alter it before finally dispatching it to the reducer.
  • listener: a function that gets called when a state is changed.

  • Add a listener to the store. The listener will be notified when the state changes.

    Example

    Adding a listener

    Add a simple listener for a MyState state type

    let subscription = store.addListener(forStateType: MyState.self) { newState in
  // Do something with the state
}

    Adding a listener with a filterBlock

    Adding a listener for a state of TodoItemsState type with a filter block. In the filterBlock we check that the new state has more items than the old state. The Listener will be notified only if the filterBlock returns true.

    let subscription = store.addListener(
  forStateType: TodoItemsState.self,
  if: { old, new in return old.todos.count > new.todos.count }) { newState in
    // Do something with the state
}

    Adding a listener with a state key

    Adding a listener for a state of TodoItemsState type, the reducer registered the state key to todos

    let subscription = store.addListener(forStateType: TodoItemsState.self, stateKey: "todos") { newState in
  // Do something with the state
}

    Declaration

    Swift

    public func addListener<StateType>(forStateType type: StateType.Type,
                                     stateKey: StateKey? = nil,
                                     if filterBlock: FilterFunction<StateType>? = nil,
                                     callback: @escaping (StateType) -> ()) -> Subscription<StateType>

    Parameters

    type

    The type of the state to listen to. If the state type is not found, the listener will not be notified.
    stateKey

    (Optional) the state key to listen to. When not passed (or passing nil) the type name from forStateType will be used. Only pass when the state key for the state was changed in the reducer (99% of the times you dont need to set this parameter)
    filterBlock

    (Optional) block that receives the old state and the new state and it decides wether the notification for the listener should be sent or not. When not set, the listener is notified whenever the state changed.
    callback

    Notification block called with the new state when the store’s state changed.

    Return Value

    The Listener’s subscription that can be used to remove the notification and for other listener related stuff.

    Show on GitHub

  • Add a listener to the store with a stateSelector

    Example

    Adding a listener with a state selector

    Add a simple listener for the full state with a state selector that selects part of it.

    Create a state selector that selects and creates a TodoItemsState from the full Store state.

    let stateSelector: StateSelector<TodoItemsState> = { state in
  // Read values from the store
  let value1 = state.value(forKeyOfType: SomeType.self)
  let value2 = state.value(forKey: "someKey")

  // Create and return a TodoItemsState
  return TodoItemsState(.....)
}

    Add a listener with the state selector and

    let subscription = store.addListener(stateSelector: stateSelector) { newState in
  // newState here is a TodoItemsState
}

    Adding a listener with a state selector and a filter block

    Add a simple listener for the full state with a state selector that selects part of it and a filter block that decide when to notify.

    Create a state selector that selects and creates a TodoItemsState from the full Store state.

    let stateSelector: StateSelector<TodoItemsState> = { state in
  // Read values from the store
  let value1 = state.value(forKeyOfType: SomeType.self)
  let value2 = state.value(forKey: "someKey")

  // Create and return a TodoItemsState
  return TodoItemsState(.....)
}

    Add a filter block that decides when to notify

    let filterBlock: FilterFunction<State> = { oldState, newState in
  // Read a string from the oldState and newState
  // oldState and newState are the full Store state
  let value1 = oldState.value(forKey: "someKey", ofType: String.self)
  let value2 = newState.value(forKey: "someKey", ofType: String.self)

  // Compare
  return value1 != value2
}

    Add a listener with the state selector and

    let subscription = store.addListener(stateSelector: stateSelector) { newState in
  // newState here is a TodoItemsState
}

    Declaration

    Swift

    public func addListener<StateType>(if filterBlock: FilterFunction<State>? = nil,
                                     stateSelector: @escaping StateSelector<StateType>,
                                     callback: @escaping (StateType) -> ()) -> Subscription<StateType>

    Parameters

    filterBlock

    (Optional) block that receives the old state and the new state and it decides wether the notification for the listener should be sent or not. When not set, the listener is notified whenever the state changed.
    stateSelector

    state selector block that selects a part of the full state
    callback

    Notification block called with the new state when the store’s state changed.

    Return Value

    The Listener’s subscription that can be used to remove the notification and for other listener related stuff.

    Show on GitHub

  • Add a listener to the store. The listener will be notified when the state changes. The listener will be notified with the full state when

    Example

    Adding a listener

    Add a simple listener for the full state.

    let subscription = addListener { newState in
  // Do something with the state

  // Get value of Any? Type with key "TheKey"
  let value1 = newState.value(forKey: "TheKey")

  // Get value of MyState? Type with key "MyState" (Key value = the type of the state we want)
  let value2 = newState.value(forKeyOfType: MyState.self)

  // Get value of MyState? Type with key "TheKey"
  let value3 = newState.value(forKey: "TheKey", ofType: MyState.self)
}

    Adding a listener with a filterBlock

    Adding a listener for the full state with a filter block. In the filterBlock we check that the new state has more than 10 items. The Listener will be notified only if the filterBlock returns true.

    let subscription = store.addListener(if: { oldState, newState in

  // Read values from the oldState and the newState
  let old = oldState.value(forKeyOfType: TodoItemsState.self)!
  let new = newState.value(forKeyOfType: TodoItemsState.self)!

  return new.todos.count > 10
}) { newState in
  // Do something with the state
}

    Declaration

    Swift

    public func addListener(if filterBlock: FilterFunction<State>? = nil,
                          callback: @escaping (State) -> ()) -> Subscription<State>

    Parameters

    filterBlock

    (Optional) block that receives the old state and the new state and it decides wether the notification for the listener should be sent or not. When not set, the listener is notified whenever the state changed.
    callback

    Notification block called with the new state when the store’s state changed.

    Return Value

    The Listener’s subscription that can be used to remove the notification and for other listener related stuff.

    Show on GitHub

  • Add a new action listner to the store. Action listeners will be notified whenever a new action is dispatched. Inside the action notification you cast to the specific ation and read the payload of the action.

    Example

    Add an action listener, this action listener will be notified when an action is dispatched.

    let subscription = addActionListener { action in

  // Cast to some of your actions
  if let action = action as? MyButtonClickedAction {
  }

  // Cast to some other action
  if let action = action as? SomeOtherAction {
  }
}

    Declaration

    Swift

    public func addActionListener(actionListener: @escaping ActionListenerFunction) -> ActionSubscription

    Parameters

    actionListener

    Notification block called when an action happens.

    Return Value

    The Listener’s subscription that can be used to remove the notification and for other listener related stuff.

    Show on GitHub

  • Reset the store internal state for a particular key. They key will be the dynamic type of state.

    Declaration

    Swift

    public func reset(state: Any)

    Parameters

    state

    the new state
    Show on GitHub

  • Reset the store internal state for a specific key

    Declaration

    Swift

    public func reset(state: Any, forKey key: StateKey)

    Parameters

    state

    the new state
    key

    the state key to set
    Show on GitHub

  • Resets the full internal state with a new state

    Declaration

    Swift

    public func resetFullState(_ state: KeyedState)

    Parameters

    state

    the state to reset to
    Show on GitHub