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 getGamesNames method for our previously coded GameRepository class that performs the simplest map operation:

public func getGamesNames() -> [String] {
    return getAll().map({ game in game.name.uppercaseString })
}

The getGamesNames parameterless method returns Array<String>. 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 a String with its name converted to uppercase. The result is an Array<String> generated by the call to the map method.

The following line uses the GameRepository instance called gameRepository to call the previously added getGamesNames...