swift : Closure declaration as like block declaration

Question

We can declare block as below in Objective-C.

typedef void (^CompletionBlock) (NSString* completionReason);

I\'m trying to do this in swift

Answer 1

Here is awesome blog about swift closure.

Here are some examples:

As a variable:

var closureName: (inputTypes) -> (outputType)

As an optional variable:

var closureName: ((inputTypes) -> (outputType))?

As a type alias:

typealias closureType = (inputTypes) -> (outputType)