Can't import lazy-loaded module's state from json using Redux DevTools

[MasDevProject]

I'm developing an application using Angular and ngrx with redux DevTools for Chrome. My application has also a lazy-loaded module and I configured it like this:

@NgModule({
    imports: [
        CommonModule,
        FormsModule,
        RouterModule.forChild([
            { path: '', component: UserLazyHistoryComponent }
        ]),
        StoreModule.forFeature(moduleFeatureName, reducers),
        EffectsModule.forFeature([
            HistoryEffects
        ])
    ],
    declarations: [UserLazyHistoryComponent]
})
export class UserLazyHistoryModule { }

and this is my reducer index file:

export const moduleFeatureName = 'user-lazy-module';

export interface UserLazySate {
    history: fromHistory.HistoryState;
}

export const reducers = {
    history: fromHistory.reducer
};

export const selectHistoryModuleState = createFeatureSelector<UserLazySate>(moduleFeatureName);

export const selectHistory = createSelector(selectHistoryModuleState, s => s.history);

With this configuration everything works well but I noticed that when I export the state of the application (as a json) using the ReduxDevTools and than I upload it, the state of the lazy module is not loaded. It remains null.

If I start the application right in the state of the lazy-laoded module and then I import the json, it works, but if I start from the beginning of the app, then I import the json, using the time-slider, when I reach the lazy module the state is null (default).

Expected behavior:

The state of lazy-loaded modules should be imported correctly from json.

Versions of NgRx, Angular, Node, affected browser(s) and operating system(s):

• "@angular/cli":"6.0.8"
• "@angular/common":"6.1.6"
• "@ngrx/router-store":"6.1.0"
• "@ngrx/store":"6.1.0"
• "@ngrx/store-devtools":"6.1.0"
• MacOs 10.13.6
• Chrome 69

[dummdidumm]

Duplicate of #919 (which was closed, but is not really solved yet, @brandonroberts maybe you should reopen it).

[brandonroberts]

Why do you consider it not resolved? Because its not released?

[dummdidumm]

#919 contains one specific use case which is not resolved yet, which explains the same problem of the issue which is reported here I think:

1. Be on a page where a lazy loaded module of some other page is not loaded yet
2. Import a JSON which, in the course of reapplying the actions, changes to the page of that lazy loaded module
3. -> Bug: Actions are reapplied to "old" reducers. There is no logic "oh, there is a page change which has a lazy loaded reducer, let's wait for it and then continue reapplying the actions".

Part of #919 was fixed through the "wait for update reducers initially", but this specific use case was not.

[SenthilKumaranC]

I am planning to introduce state management layer in my official angular project , I want to show a demo to team that how we can replay actions by importing jsons , but facing the same above mentioned issue. If this got resolved , then I can conduct the magic show to the team.

I am planning to add deffered actions queue in root metareducer and execute those actions again on lazy module load. But , is there anyway to check those actions are already added to store or not. Do we have any action collection to check incoming action present or not?

[dummdidumm]

There is a "update reducers" action I think, which is called everytime a new reducer is added. If you load the app with devtools open you should see these actions. But this would be only a workaround on your side. To really fix this, we need to finish what was started in #955 .

[SenthilKumaranC]

I can able to retain state now with lazy loading reducers but not using update reducers. I have maintained a deferred action collection , on module load ngOnit executing the action collection in side effect. For time being , this is ok for me.

One drawback is for each action call , there will be two calls - failed action call and success action call while replaying.