         self.term = term
         self.content = content
         self.campaign = campaign
+        self.enable = [source, medium, term, content, campaign].reduce(false) { $0 || $1 != nil }
     }
     
 }
 
 /// Encodable conformance.
-extension GoogleAnalytics: Encodable {
+public extension GoogleAnalytics {
     
     public enum CodingKeys: String, CodingKey {
         case enable


/// The `GoogleAnalytics` class is used to toggle the Google Analytics setting,
/// which adds GA parameters to links in the email.
public struct GoogleAnalytics {
    
    // MARK: - Properties
    //=========================================================================

        case campaign   = "utm_campaign"
    }
    
}
