Digested

I have been using something similar undoables for an undo/redo function in my reducers. This implementation maintains the last array in memory, which would consume quite a few resources, so I rewrote it to keep the changed documents available for redo, and implemented effects to update the persistent storage. Worked fine in ngrx/store v2. And in ngrx/store v4 if I didn't use AOT. The feared Error: Error encountered resolving symbol values statically.

In my reducer definition I had code that looked like this:

export const reducers: ActionReducerMap = {
    connection: fromConnections.reducer,
    contactlist: undoable(fromContactList.reducer),
    contactemails: undoable(fromContactEmail.reducer),
    contactphones: undoable(fromContactPhone.reducer),
    contactwebsite: undoable(fromContactWebsite.reducer),
};

undoable gets a reducer as a parameter and returns it. AOT doesn't like it.

So there are two solutions.

You can provide the reducers.

export const REDUCER_TOKEN = new InjectionToken>('Registered Reducers');

export const reducerProvider = [
    { provide: REDUCER_TOKEN, useValue: reducers },
];

export function undoableLayoutReducer(state: any, action: Action): fromLayout.State {
    return undoable(fromLayout.reducer)(state, action);
}

export const reducers: ActionReducerMap = {
    layout: undoableLayoutReducer,
};

which encapsulates the factory function in something that AOT likes. Right now this is required if you have a factory for your reducer in a feature store, as the forFeature doesn't as yet work with providers.