PropertyWrapper.swift

@propertyWrapper
struct EmailValidated {
    private var value: String?
    
    var wrappedValue: String? {
        get {
            return value
        }
        set {
            value = {
                guard let trimmedString = newValue?.trimmingCharacters(in: .whitespacesAndNewlines) else { return nil }
                return validate(trimmedString)
            }()
        }
    }
}