Support slice reducers

[mauron85]

Some reducers need to access state from different slice of state as written in
http://redux.js.org/docs/recipes/reducers/BeyondCombineReducers.html#sharing-data-between-slice-reducers

Example

const undoableDeliveriesReducer = undoable(deliveriesReducer);
const undoableRoutesReducer = undoable(routesReducer)

export default function entitiesReducer(state = defaultState, action) {
  return {
    couriers: couriersReducer(state.couriers, action),
    deliveries: undoableDeliveriesReducer(state.deliveries, action),
    routes: undoableRoutesReducer(state.routes, action, state.deliveries),
  };
}

Currently undoable only pass state and action to actual reducers, so in case of routesReducer state.deliveries will be null. Fix should be easy.

[davidroeca]

Hi @mauron85 I just made a pull request for this issue

[mauron85]

Nice. In meantime I realised that redux-undo is not suitable for my use case as I need to undo actions, not just revert state of the UI.

[davidroeca]

@mauron85 what's the difference in that case? If your reducer is undoable, then the state changes associated with the action will be undone. The action will be undone, no?

If you're referring to thunk actions (actions that have side-effects that result in more actions), you can look into filtering.

[mauron85]

I also need to undo action on the server, but I cannot determine which action it was from state change. And redux-undo, only store state changes, not action types/names which lead to those changes. Hopefully I expressed myself clearly. :-)

[davidroeca]

I see, so not a redux action but an API call. Yeah, undoing side effects outside the redux store is outside the scope of this library. I assume there would have to be specific logic for each back-end call to undo the call. Though in either case I don't think there would be a simple way to undo a deletion

[mauron85]

Yes, https://github.com/powtoon/redux-undo-redo is doing it in custom middleware and revertingActions. Anyway for state/UI only undos, your module is perfect.

[davidroeca]

Ah interesting, definitely provides a backend-compatible solution at the cost of usability. I'm thinking this sort of functionality could be incorporated into this library as a config option. I'll look into it when I have the time

[davidroeca]

Created a new issue (#150) and closing this one since the PR has been merged