When should I compare an optional value to nil?

Question

Quite often, you need to write code such as the following:

if someOptional != nil {
    // do something with the unwrapped someOptional e.g.       
    someF         


        

Answer 1

After lot of thinking and researching i have came up with the easiest way to unwrap an optional :

• Create a new Swift File and name it UnwrapOperator.swift

• Paste the following code in the file :

  import Foundation
  import UIKit
  
  protocol OptionalType { init() }
  
  extension String: OptionalType {}
  extension Int: OptionalType {}
  extension Int64: OptionalType {}
  extension Float: OptionalType {}
  extension Double: OptionalType {}
  extension CGFloat: OptionalType {}
  extension Bool: OptionalType {}
  extension UIImage : OptionalType {}
  extension IndexPath : OptionalType {}
  extension NSNumber : OptionalType {}
  extension Date : OptionalType {}
  extension UIViewController : OptionalType {}
  
  postfix operator *?
  postfix func *?( lhs: T?) -> T {
  
      guard let validLhs = lhs else { return T() }
      return validLhs
  }
  
  prefix operator /
  prefix func /( rhs: T?) -> T {
  
      guard let validRhs = rhs else { return T() }
      return validRhs
  }
  

• Now the above code has created 2 operator [One prefix and one postfix].

• At the time of unwrapping you can use either of these operator before or after the optionals

• The explanation is simple, the operators returns the constructor value if they get nil in variable else the contained value inside the variable.

• Below is the example of usage :

  var a_optional : String? = "abc"
  var b_optional : Int? = 123
  
  // before the usage of Operators
  
  print(a_optional) --> Optional("abc")
  print(b_optional) --> Optional(123)
  
  // Prefix Operator Usage
  
  print(/a_optional) --> "abc"
  print(/b_optional) --> 123
  
  // Postfix Operator Usage
  
  print(a_optional*?) --> "abc"
  print(b_optional*?) --> 123
  

• Below is the example when variable contains nil :

  var a_optional : String? = nil
  var b_optional : Int? = nil
  
  // before the usage of Operators
  
  print(a_optional) --> nil
  print(b_optional) --> nil
  
  // Prefix Operator Usage
  
  print(/a_optional) --> ""
  print(/b_optional) --> 0
  
  // Postfix Operator Usage
  
  print(a_optional*?) --> ""
  print(b_optional*?) --> 0
  

• Now it is your choice which operator you use, both serve the same purpose.