Implementing OnInitEffects with functionalEffects

[Clindbergh]

Which @ngrx/* package(s) are relevant/related to the feature request?

effects

Information

Is it possible to use createEffect to implement the OnInitEffects interface to trigger initial effects?

Describe any alternatives/workarounds you're currently using

No response

I would be willing to submit a PR to fix this issue

• Yes
• No

[timdeschryver]

This isn't supported.
What's the use case that you have on your mind that does need this feature?

[Clindbergh]

We have one file with (functional) effects:

effects.ts:

export const updateUrl = createEffect(
   ...
, { functional: true })

export const doFoo = createEffect(
   ...
, { functional: true })

export const getBar = createEffect(
   ...
, { functional: true })

We use them in our feature.module.ts:

import * as Effects from '../effects';

@NgModule({
  imports: [
    EffectsModule.forFeature(Effects),
  ],
})
export class FeatureModule {}

We would like to place the new initial effect in effect.ts:

export class LoadVacanciesEffects implements OnInitEffects {
  ngrxOnInitEffects(): Action {
    return ListActions.PageEntered();
  }
}

However this does not work, since the EffectsModule.forFeature call would now be invalid using the * import. It is therefore required to place this single Initial effect in a separate file which feels a bit awkward.

[timdeschryver]

I do find it weird to add a lifecycle to the functional effects.
After thinking on this for a while, what about moving the lifecycle hook to provideEffects?

provideEffects(myEffects, { dispatchOnInit: myEffectsLoaded() })

[Hetty82]

That would help, but not the same. The cool thing about the OnInitEffect is that it only runs once, no matter how often it is provided in features. It was perfect for loading data for a feature for me. But we can always go back to using a concatLatestFrom(() => store.select(isLoaded)).