CODEWITHSUNDEEP
iosswiftenumsswitch-statement
Isuru
Isuru

Reputation: 31313

Duplicated code in switch cases that needs executing

I have the following enum which handles the UI state.

enum UIState {
    case loading
    case populated
    case empty
    case error(Error)
}

In view controllers, I use a switch to check against each state and update the UI accordingly.

private func updateUI() {
    switch state {
    case .loading:
        showProgressView()
    case .populated, .empty:
        hideProgressView()
    case .error(let error):
        hideProgressView()
        showErrorAlert(error)
    }
}

The hideProgressView() method needs to be called in all cases except loading. In the error case, I am showing an alert in addition to calling the hideProgressView() method.

As you can see there is a small duplication of code where I'm calling the hideProgressView() method in two cases. Is there a way to consolidate the repeating method calls under one case? I tried the following way,

switch state {
case .loading:
    showProgressView()
case .error(let error):
    showErrorAlert(error)
case .populated, .empty, .error:
    hideProgressView()
}

But I get the following warnings on the last case.

Case is already handled by previous patterns; consider removing it

Case will never be executed

Upvotes: 0

Views: 79

Answers (1)

Nikola Ristic
Nikola Ristic

Reputation: 449

Maybe the easiest way would be something like this:

switch state {
    case .loading:
        showProgressView()
    case .error(let error):
        showErrorAlert(error)
        fallthrough
    case .populated, .empty:
        hideProgressView()
    }

You can get more info at: https://docs.swift.org/swift-book/LanguageGuide/ControlFlow.html#ID140

Upvotes: 2

Related Questions