Dealing with Optionals' functionally

We have covered different approaches and tools to deal with Optionals so far. Let's examine if we can use functional programming paradigms to simplify the process.

Optional mapping

Mapping over an array would generate one element for each element in the array. Can we map over an optional to generate non-optional values? If we have some, map it; otherwise, return none. Let's examine the following code:

func mapOptionals<T, V>(transform: (T) -> V, input: T?) -> V? { 
    switch input { 
    case .some(let value): return transform(value) 
    case .none: return .none 
    } 
} 

Our input variable is a generic optional and we have a transform function that takes input and transforms it into a generic type. The result will be a generic optional type. In the function body, we use pattern matching to return the respective values. Let's test this function:

class User { 
    var name: String? 
} 

We create a class named User with an optional variable. We...