What is wrapped?

wrapped is the value of an optional type after successfully extracting (unwrapping) its contents. An Optional<<Wrapped>> optional either holds a value of type Wrapped or is nil. Extraction allows access to the Wrapped value if it exists.

Examples of extraction:

1. Forced unwrapping !:

   var optionalString: String? = "Hello"
   let unwrappedString = optionalString! // Gets the value "Hello"
   // If optionalString == nil, a crash occurs
   

2. Optional binding if let or guard let:

   var anotherOptionalString: String? = "World"
   if let guaranteedString = anotherOptionalString {
       // Inside this block, guaranteedString is of type String (unwrapped)
       print(guaranteedString)
   }
   

3. Optional chaining ?:

   class MyClass { var property: String? }
   var instance: MyClass? = MyClass()
   instance?.property = "Value" // If instance is not nil, the property is set
   let retrievedValue = instance?.property // retrievedValue will be String?
   

4. Nil-coalescing operator ??:

   var yetAnotherOptionalString: String? = nil
   let defaultValue = yetAnotherOptionalString ?? "Default" // defaultValue will be "Default" (String)
   // If yetAnotherOptionalString had a value, it would be used as unwrapped.
   

In the context of Swift, a wrapped value is the actual content that was "inside" the optional before it was unwrapped.