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@bigus-dickus thanks for your reply, I hope I understand correctly: So instead of trying to chain/await external actions/events, I simply subscribe to all the required states within my main effect, merge these subscriptions somehow, and finally dispatch InitSuccess when every required state has e.g. loaded:true?
Still a bit confused on how to write this in detail, but sounds really good to me. Could you guide me to a snippet where something similar is done? -
TLDR: don't try to handle this in a single effect.
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First of all, create the 3 loading effects (takes a Whatever.Load action, calls your service, dispatches Whatever.LoadSuccess or Whatever.LoadFailure accordingly)
Then, create relaying effects. For instance, one could be Mountains.LoadSuccess -> Streets.Load. Or, if you want to do parallel loading: World.Init -> [Mountains.Load, Streets.Load, Rivers.Load] -
@Commodore thanks a lot. My problem is that I don't want to write effects like Mountains.LoadSuccess -> Streets.Load, since they should not depend on each other. Streets should still work, wether or not Mountains are there. I want to be able to reload Mountains without reloading Streets.
However, parallel loading is what I am trying right now. While this works fine:
World.Init -> [Mountains.Load, Streets.Load, Rivers.Load]
I am not sure how to achieve this from a World effect:
[Mountains.LoadSuccess, Streets.LoadSuccess, Rivers.LoadSuccess] -> World.InitSuccess -
@Minion was about to suggest something along this line:
subscribe to all 3 LoadSuccess and check the state each time.
@sboesch i'm not fond of the sequence either but for accuracy's sake: each load effect will work independantly. What could be bothersome is that firing a Streets.Load would trigger Rivers.Load later on. That could be handled by adding a boolean to your action's payload, enabling/disabling the chain.
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Nowadays......¯\_(ツ)_/¯
Just Angular thing
I'm having problems understanding ngrx (or simply rxjs...), once again.
I have a feature state called "World".
This state has three Actions: Init, InitSuccess and InitFailure.
Also I have other isolated feature states like "Mountains", "Streets", "Rivers".
They have actions like this and corresponding effects to fetch data: Load, LoadSuccess, LoadFailure.
Now I would like to add an effect to WorldActions.Init, which will dispatch Mountains.Load, Streets.Load, Rivers.Load one after another. So ideally an action log would look like this:
1. World.Init
2. Mountains.Load
3. Streets.Load
4. Rivers.Load
5. Mountains.LoadSuccess
6. Streets.LoadSuccess
7. Rivers.LoadSuccess
8. World.InitSuccess
Or when an error occurs:
1. World.Init
2. Mountains.Load
3. Mountains.LoadFailure
4. World.InitFailure
How could an effect pipeline for that look?
How can I dispatch World.InitSuccess only after all LoadSuccess-Actions have happened?
Or am I still trying to implement ngrx in a wrong/bad way?
PS: The reason I am putting everything into separate feature states is because "Mountains" etc. are standalone features on their own. Only in the context of a "World" they belong together. For this reason I can't create a monstrous effect "World.Load", without producing redundant code.
question
rxjs
angular
ngrx