How to use async/await in SwiftUI

Depending on the scenario, there are different ways to use Swift's async/await syntax in SwiftUI. We might want to call an asynchronious function for example when:

• a SwiftUI view appears
• as a response to a user action like a button tap or a pull to refresh

Using the task view modifier

In the scenario where we want to do some asynchronious work when a view appears, SwiftUI provides the task modifier.

var body: some View {
    Text(viewModel.status)
        .task {
            await viewModel.refreshStatus()
        }
}

In the example above, as soon as the Text view appears, SwiftUI will create a task and will also cancel it when the view disappears.

Calling the async static function

In the scenario where we want to do some asynchronious work when the user taps a button, we can use the Task type.

Button("refresh status") {
    Task {
        await viewModel.refreshStatus()
    }
}

Using the refreshable view modifier

In the scenario where we want to refresh some data on a pull to refresh, we can use the refreshable modifier.

List {
    ...
}
.refreshable {
    await viewModel.refreshMessages()
}

The modifier takes an async action that SwiftUI will execure as soon as the user performs the refresh gesture.