Extensions in Swift
In Swift, an extension is a way to add new functionality to an existing class, structure, enumeration, or protocol type. This can include adding new methods, computed properties, and initializers, as well as providing new implementations of existing methods, properties, and subscripts. Extensions can be used to extend the functionality of any type, including built-in types, user-defined types, and even types defined in other libraries or frameworks.
Here is an example of using an extension in Swift to add new functionality to an existing type:
// Define a new Int type that represents a number of seconds
typealias Seconds = Int
// Define an extension on the Int type to add a new computed property
extension Int {
var minutes: Seconds {
return self * 60
}
}
// Use the new property to convert seconds to minutes
let sixtySeconds = 1.minutes
print(sixtySeconds) // Output: 60
In this example, we define a new typealias called Seconds to represent a number of seconds. We then define an extension on the Int type to add a new computed property called minutes. This property returns the number of seconds converted to minutes by multiplying the number of seconds by 60. Finally, we use the new minutes property to convert 1 second to minutes and print the result.