Modeling Async Images

[Dg00]

Hi ,
I recently started TCA journey and completely new to functional world.
there is a view i am trying to make which basically has a image view the flow is like

show view with placeholder -> trigger download of image with a url -> (success , failure) -> (remoteImage/ fallback).

strictly speaking these are seem to be effects as there is no user interaction involved and hence no actions. I cheat a bit by assuming that view's onAppear() is kind of a user intent and trigger my download.
Another question is how does TCA handle 2 way bindings like in gesture state are we supposed to send a drag event for every value emitted by gesture ?

[kamcma]

It's not cheating to have onAppear trigger an effect (via an action). As a rule of thumb, actions should represent either UI events (whether directly user-initiated or not, such as an onAppear closure firing), or emissions from effects.

Specifically on loading image data from the network, though, you may be interested in SwiftUI's AsyncImage view. For most of us, loading remote image data isn't our core business logic, so there's really no reason to handle that manually in a reducer; just outsource that to SwiftUI.

[kamcma]

On binding things like gesture state, you can send an action for every event. You could also throttle or debounce events depending on what your reducer needs to know. This section of the docs about high-frequency actions touches on this topic.

[Dg00]

Thanks for confirming, I wanted to be sure that I am not going against the core philosophy at my first TCA project. I am using a wrapper around SDWebimage swiftui for async images to send actions based on the state of download. There is lot more I have to handle like deeplinks , analytics , custom labels so i cant treat it as a plain view with download logic.

Thanks for pointing to right doc, will give it a thorough read.