How does one make an optional closure in swift?

by

You should enclose the optional closure in parentheses. This will properly scope the ? operator.

func then(onFulfilled: ()->(), onReject: (()->())?){       
    if let callableRjector = onReject {
      // do stuff! 
    }
 }

More Related Contents:

  1. How to seed the Int.random method call in Swift?
  2. Migrating Swift code to Swift 3.0 LOADS of errors
  3. Overriding methods in Swift extensions
  4. Alternative to performSelector in Swift?
  5. NSObject subclass in Swift: hash vs hashValue, isEqual vs ==
  6. creating custom tableview cells in swift
  7. Return instancetype in Swift
  8. Swift protocol extension method is called instead of method implemented in subclass
  9. NSURLSession concurrent requests with Alamofire
  10. Does Swift have documentation generation support?
  11. Get integer value from string in swift
  12. Why constant constraints the property from a structure instance but not the class instance?
  13. == overload for custom class is not always called
  14. Is it possible to replicate Swifts automatic numeric value bridging to Foundation (NSNumber) for (U)Int8/16/32/64 types?
  15. Sheet inside ForEach doesn’t loop over items SwiftUI
  16. Does swift copy on write for all structs?
  17. Fetch data from CoreData for iOS 14 widget
  18. fatal error: swapping a location with itself is not supported with Swift 2.0
  19. How do I import a Swift file from another Swift file?
  20. What is the point of having two different names for the same parameter?
  21. Swift lazy instantiating using self
  22. Swift – How to mutate a struct object when iterating over it
  23. How to use a @FetchRequest with the new searchable modifier in SwiftUI?
  24. No such module ‘RestKit’ with cocoapods and swift
  25. What’s the difference between using ARAnchor to insert a node and directly insert a node?
  26. Use Cocoapods with an App Extension
  27. How to remove “row” separators/dividers from a List in SwiftUI?
  28. Increase the size of the indicator in UIPageViewController’s UIPageControl
  29. How do I programmatically move an ARAnchor?
  30. Whats the Swift animate WithDuration syntax?

Leave a Comment