Trait reactive_state::middleware::Middleware

pub trait Middleware<State, Action, Event, Effect> {
    fn on_reduce(
        &self, 
        store: &Store<State, Action, Event, Effect>, 
        action: Option<&Action>, 
        reduce: ReduceFn<State, Action, Event, Effect>
    ) -> ReduceMiddlewareResult<Event, Effect> { ... }
    fn process_effect(
        &self, 
        _store: &Store<State, Action, Event, Effect>, 
        effect: Effect
    ) -> Option<Effect> { ... }
    fn on_notify(
        &self, 
        store: &Store<State, Action, Event, Effect>, 
        events: Vec<Event>, 
        notify: NotifyFn<State, Action, Event, Effect>
    ) -> Vec<Event> { ... }
}

Middleware used to modify the behaviour of a Store during a Store::dispatch().

Provided methods

fn on_reduce(
    &self,
    store: &Store<State, Action, Event, Effect>,
    action: Option<&Action>,
    reduce: ReduceFn<State, Action, Event, Effect>
) -> ReduceMiddlewareResult<Event, Effect>

This method is invoked by the Store during a Store::dispatch() just before the Action is sent to the Reducer. It is necessary to call the provided reduce function, which executes subsequent middleware and runs the Reducer, and usually the events produced by the reduce function are returned from this method.

This method allows modifying the action in question, or even removing it, preventing the Reducer from processing the action. It also allows modifying the events produced by the Reducer before the Middleware::on_notify() is invoked and they are sent to the Store listeners.

fn process_effect(
    &self,
    _store: &Store<State, Action, Event, Effect>,
    effect: Effect
) -> Option<Effect>

Process an Effect. Returns None if the effect was processed/consumed by this handler, otherwise returns Some(effect).

fn on_notify(
    &self,
    store: &Store<State, Action, Event, Effect>,
    events: Vec<Event>,
    notify: NotifyFn<State, Action, Event, Effect>
) -> Vec<Event>

This method is invoked by the Store during a Store::dispatch() after the Reducer has processed the Action and all Middleware::on_reduce() methods have completed, just before resulting events are sent to the store listeners. It is necessary to call the provided notify function, which executes subsequent middleware and then notifies the listeners.

This method allows modifying the events in question before the listeners are notified.

Implementors

impl<State, Action, Event, Effect> Middleware<State, Action, Event, Effect> for SimpleLoggerMiddleware where
    Event: Clone + Hash + Eq + Debug,
    State: Debug,
    Action: Debug,
    Effect: Debug, 

This is supported on crate feature simple_logger only.

fn on_reduce(
    &self,
    store: &Store<State, Action, Event, Effect>,
    action: Option<&Action>,
    reduce: ReduceFn<State, Action, Event, Effect>
) -> ReduceMiddlewareResult<Event, Effect>

fn process_effect(
    &self,
    _store: &Store<State, Action, Event, Effect>,
    effect: Effect
) -> Option<Effect>

fn on_notify(
    &self,
    store: &Store<State, Action, Event, Effect>,
    events: Vec<Event>,
    notify: NotifyFn<State, Action, Event, Effect>
) -> Vec<Event>

impl<State, Action, Event, Effect> Middleware<State, Action, Event, Effect> for WebLoggerMiddleware where
    State: Serialize,
    Action: Serialize + Display,
    Event: Clone + Hash + Eq + Serialize,
    Effect: Serialize, 

This is supported on crate feature web_logger only.

fn on_reduce(
    &self,
    store: &Store<State, Action, Event, Effect>,
    action: Option<&Action>,
    reduce: ReduceFn<State, Action, Event, Effect>
) -> ReduceMiddlewareResult<Event, Effect>

fn process_effect(
    &self,
    _store: &Store<State, Action, Event, Effect>,
    effect: Effect
) -> Option<Effect>

fn on_notify(
    &self,
    store: &Store<State, Action, Event, Effect>,
    events: Vec<Event>,
    notify: NotifyFn<State, Action, Event, Effect>
) -> Vec<Event>