LiftToCollectionMiddleware

@available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
public struct LiftToCollectionMiddleware<
    GlobalInputActionType,
    GlobalOutputActionType,
    GlobalStateType,
    CollectionState: MutableCollection,
    PartMiddleware: MiddlewareProtocol>: MiddlewareProtocol
where PartMiddleware.StateType: Identifiable, CollectionState.Element == PartMiddleware.StateType

This is a container that lifts a sub-state middleware to a global state middleware.

Internally you find the middleware responsible for handling events and actions for a sub-state (Part), while this outer class will be able to compose with global state (Whole) in your Store.

You should not be able to instantiate this class directly, instead, create a middleware for the sub-state and call Middleware.liftToCollection(_:), passing as parameter the keyPath from whole to part.

  • Declaration

    Swift

    @available(*, deprecated, message: "Instead of relying on receiveContext, please use the getState from handle(action﹚ function,\nand when returning IO from the same handle(action﹚ function use the output from the closure")
public func receiveContext(getState: @escaping () -> GlobalStateType, output: AnyActionHandler<GlobalOutputActionType>)

  • Handles the incoming actions and may or not start async tasks, check the latest state at any point or dispatch additional actions. This is also a good place for analytics, tracking, logging and telemetry. Because the lift middleware is derived from a sub-state/sub-action middleware, every global action received will be mapped into a sub-action, in a operation that can return nil (Optional<SubAction>). In case it’s nil, it means that the sub-action middleware doesn’t work with this type of action, so the lifted middleware will simply call the next middleware in the chain. On the other hand, if this operation returns a non-nil local action, this local action will be handled by the child middleware, which is also responsible for calling next() in this case. When the State type is also lifted, the context property will translate the global state into local state as expected every time you call context().getState().

    • action: the action to be handled
    • dispatcher: information about the file, line and function that dispatched this action
    • state: a closure to obtain the most recent state

    Declaration

    Swift

    public func handle(action: GlobalInputActionType, from dispatcher: ActionSource, state: @escaping GetState<GlobalStateType>)
-> IO<GlobalOutputActionType>

    Return Value

    possible Side-Effects wrapped in an IO struct