Wrapper for Variable in RxSwift that allows easy transformation rules for the input values

TransformingVariable.swift

public class TransformingVariable<Element> : ObserverType, ObservableConvertibleType {
    public typealias E = Element
    public typealias TransformationBlock = (_ input: E) -> E
    
    private let backingVariable: Variable<E>
    private let transformation: TransformationBlock
    
    public init(initialValue: E, transformation: @escaping TransformationBlock) {
        self.backingVariable = Variable(initialValue)
        self.transformation = transformation
    }
    
    public var value: E {
        set(value) {
            self.backingVariable.value = self.transformation(value)
        }
        
        get {
            return self.backingVariable.value
        }
    }
    
    public func asObservable() -> Observable<E> {
        return self.backingVariable.asObservable()
    }
    
    public func on(_ event: Event<E>) {
        switch event {
        case .next(let element):
            self.value = element
        default:
            break
        }
    }
}