Update StatsEmailFollowersInsight to use Codable

Author: staskus

WordPressKit/Insights/StatsEmailFollowersInsight.swift

@@ -1,4 +1,4 @@
-public struct StatsEmailFollowersInsight {
+public struct StatsEmailFollowersInsight: Codable {
     public let emailFollowersCount: Int
     public let topEmailFollowers: [StatsFollower]
 
@@ -7,6 +7,11 @@ public struct StatsEmailFollowersInsight {
         self.emailFollowersCount = emailFollowersCount
         self.topEmailFollowers = topEmailFollowers
     }
+
+    private enum CodingKeys: String, CodingKey {
+        case emailFollowersCount = "total_email"
+        case topEmailFollowers = "subscribers"
+    }
 }
 
 extension StatsEmailFollowersInsight: StatsInsightData {
@@ -22,17 +27,12 @@ extension StatsEmailFollowersInsight: StatsInsightData {
     }
 
     public init?(jsonDictionary: [String: AnyObject]) {
-        guard
-            let subscribersCount = jsonDictionary["total_email"] as? Int,
-            let subscribers = jsonDictionary["subscribers"] as? [[String: AnyObject]]
-            else {
-                return nil
+        do {
+            let jsonData = try JSONSerialization.data(withJSONObject: jsonDictionary, options: [])
+            let decoder = JSONDecoder()
+            self = try decoder.decode(StatsEmailFollowersInsight.self, from: jsonData)
+        } catch {
+            return nil
         }
-
-        let followers = subscribers.compactMap { StatsFollower(jsonDictionary: $0) }
-
-        self.emailFollowersCount = subscribersCount
-        self.topEmailFollowers = followers
     }
-
 }