Ngrx State between pages in Ionic 4


I am migrating an app from v3 to v4 and I am finding some problems. I used to load some data in v3 only once like user profile. I did it from a service which was shared between all pages. Now, in v4, that service gets constructed each time I change from page although it is configured as root:

@Injectable({ providedIn: 'root' })

After some readings, It is supposed using ngrx is a good option. After some code I can see app state object isn’t maintained in memory between pages, so which is the best practice/pattern to get some data in memory loaded only when app starts?