Articles, podcasts and news about Swift development, by John Sundell.

Calling initializers with dot syntax and passing them as closures

Published on 25 Mar 2017

Cool thing about Swift initializers: you can call them using dot syntax and pass them as closures! Perfect for mocking dates in tests.

class Logger {
    private let storage: LogStorage
    private let dateProvider: () -> Date
    
    init(storage: LogStorage = .init(), dateProvider: @escaping () -> Date = Date.init) {
        self.storage = storage
        self.dateProvider = dateProvider
    }
    
    func log(event: Event) {
        storage.store(event: event, date: dateProvider())
    }
}

Support Swift by Sundell by checking out this sponsor:

Essential Developer

Essential Developer: Learn the most up-to-date techniques and strategies for testing new and legacy Swift code in this free practical course for developers who want to become complete senior iOS developers. This virtual event includes lectures, mentoring sessions, and step-by-step instructions. Click to learn more.