What is the meaning of var something: (() -> Void)? in Swift

Asked Dec 05 '18 at 16:25

Active Dec 05 '18 at 16:25

Viewed 162 times

Just reading through some docs I see declarations like this

  var loginSuccess: (() -> Void)?

throughout the code, I was wondering what this is called and what it's use case would be?

In this example I see

loginVC.loginSuccess = {
    self.activityIndicator.startAnimating()
    self.dismissViewControllerAnimated(true) {
        self.viewModel.fetchThreats()
    }
}

So I'm assuming it's just a closure that be invoked when an action completes. Returns nothing and accepts nothing?

asked Dec 05 '18 at 16:25

Harry Blue

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That's what it looks like to me. – Robert Harvey Dec 05 '18 at 16:26
3

Please read the [Closures](https://docs.swift.org/swift-book/LanguageGuide/Closures.html) chapter in the Swift book. – rmaddy Dec 05 '18 at 16:26
As said by rmaddy, the keyword you miss is `Closure`. It's also called "Block" in Objective-C. – Larme Dec 05 '18 at 16:28
1

An *optional* closer that takes and returns nothing, correct. – Kevin Dec 05 '18 at 16:28

What is the meaning of var something: (() -> Void)? in Swift

0 Answers0