Services lifecycle (destroy a service)

user_3471528 0
Viewed 2756

My application has an architecture as follows: enter image description here

Once the user log in, I navigate to the MainModule (lazy) where I register the services used in the MainModule's components. CarService caches the result of the webservice so, if the user logs out, I need this service to be destroyed. When the user logs out I navigate to the LoginModolue.

I thought that navigating to the LoginModule, the MainModule would have been destroyed (in fact I register it in the MainModule, not in the AppModule) but I noticed that if I log in again the old cache is still there. Is this normal? Shouldn't be destroyed the services provided in the MainModule when I navigate to the LoginModule?

angular-module angular-router angular
2 Answers

You would expect that to happen, unfortunately because of the nature of lazy modules, this is not what happens, read here why not. Basically the lazy loaded module stays in the memory.

What you can do however is put the provider on the main component view:

@NgModule({
  declarations: [
     MainComponent
  ]
})
export class MainModule {}

@Component({
  //...
  providers: [ CarService ]
})
export class MainComponent {}

This will destroy the CarService instance when the MainComponent gets destroyed

user_31069200

That's not the case. Moving to some other module won't mean that the previously Lazy Loaded Module will be destroyed. It would still remain. That's why Angular doesn't request for the Chunk of that Lazy Loaded Module when we try to navigate again to that Module.

The service will also remain in the memory. Only when the user manually reloads the App, will the service get reinitialized.

You'll have to manually clean the cache before navigating the user to the /login route. The ideal place for doing this can be in the ngOnDestroy of the Component that you're navigating away from.

user_26222920
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