Closures with no return value

Until now, all the closures you’ve seen have taken one or more parameters and have returned values. But just like functions, closures aren’t required to do these things. Here’s how you declare a closure that takes no parameters and returns nothing:

let voidClosure: () -> Void = { print("Swift Apprentice is awesome!")

}

voidClosure()

The closure’s type is () -> Void. The empty parentheses denote there are no parameters. You must declare a return type, so Swift knows you’re declaring a closure. This is where Void comes in handy, and it means exactly what its name suggests: the closure returns nothing.