You can turn any Swift Error into an NSError, which is super useful when pattern matching with a code. Also, switching on optionals is pretty cool!

let task = urlSession.dataTask(with: url) { data, _, error in
    switch error {
    case .some(let error as NSError) where error.code == NSURLErrorNotConnectedToInternet:
        presenter.showOfflineView()
    case .some(let error):
        presenter.showGenericErrorView()
    case .none:
        presenter.renderContent(from: data)
    }
}

task.resume()

Soulver

The perfect calculation companion for developers. Calculate anything — from dates, to budgets and prices, to what value to use as input for an algorithm. With variables, natural language processing, inline results, and more — it’s like Swift Playgrounds, but for math calculations.

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