polling feature and direct communication between reducers

[mortifactor]

Hello.
I would like to ask for help. I am quite a novice in IOS development and in TCA either.
I want to implement a case when a client in my app taps a "pay" button, receives 200 response from api and an app starts polling periodically my back-end server for "finished" order status. All this process happens in one modal sheet. In addition to this: if user closes this sheet there might be a small card on main screen with some polling animation.
I ended up with an "OrderPrepareFeature" reducer with ".payButtonTapped" action in the end and a corresponding view. But I am stuck with the polling.
I think it should be separate PollingFeature with polling logic. I suppose I can implement this in my root feature so my modal sheet or main screen could have an access to this polling state.

But how, for example, can I send the ".startPolling" action to the "PollingFeature" from my "OrderPrepareFeature" directly?
Or is my whole idea wrong and there might be a better solution?

Thanks in advance.

[mbrandonw]

Hi @mortifactor, it's really hard to say without more information. You say that polling should happen after receiving a 200 from an API request, and so technically all of that could happen directly in one single effect:

case .payButtonTapped:
  …
  return .run { send in 
    let response = try await self.apiClient.request(…)
    await send(.response(response))

    for await _ in self.clock.interval(for: .seconds(1)) {
      try await self.apiClient.poll()
      …
    } 
  }

This effect makes the API request, and if it succeeds, right after it starts a timer with a clock so that it can invoke a poll endpoint on the API.

But also, if you are completely new to iOS development and SwiftUI, I think you may be taking too big of a leap with TCA. I would highly recommend becoming more familiar with the fundamentals of Apple's platforms before jumping into an opinionated library like TCA.