Using map to transform values

The map method takes a closure as an argument, calls it for each item in the array, and returns a mapped value for the item. The returned mapped value can be of a different type from the item's type.

The following lines declare a new getUppercasedNames method for our previously coded GameRepository class that performs the simplest map operation. The code file for the sample is included in the swift_3_oop_chapter_07_21 folder:

    open func getUppercasedNames() -> [String] { 
      return getAll().map({ game in game.name.uppercased() }) 
    } 

The getUppercasedGames parameterless method returns Array<String>, specified with the [String] shortcut. The code calls the getAll method and calls the map method for the result with a closure that returns the name value for each game converted to uppercase. This way, the map method transforms each Game instance into String with its name converted to uppercase. The result is an Array<String> ...