Use system ISO8601DateFormatter

DB/Sources/DB/Content/ContentDatabaseJSONEncoder.swift

@@ -7,11 +7,12 @@ final class ContentDatabaseJSONEncoder: JSONEncoder {
     override init() {
         super.init()
 
-        let dateFormatter = DateFormatter()
-
-        dateFormatter.dateFormat = Constants.dateFormat
-        dateEncodingStrategy = .formatted(dateFormatter)
         keyEncodingStrategy = .convertToSnakeCase
         outputFormatting = .sortedKeys
+        dateEncodingStrategy = .custom { date, encoder in
+            var container = encoder.singleValueContainer()
+
+            try container.encode(MastodonDecoder.dateFormatter.string(from: date))
+        }
     }
 }

Mastodon/Sources/Mastodon/Coding/MastodonDecoder.swift

@@ -6,10 +6,26 @@ public final class MastodonDecoder: JSONDecoder {
     public override init() {
         super.init()
 
-        let dateFormatter = DateFormatter()
-
-        dateFormatter.dateFormat = Constants.dateFormat
-        dateDecodingStrategy = .formatted(dateFormatter)
         keyDecodingStrategy = .convertFromSnakeCase
+        dateDecodingStrategy = .custom { decoder in
+            let container = try decoder.singleValueContainer()
+            let dateString = try container.decode(String.self)
+
+            guard let date = Self.dateFormatter.date(from: dateString) else {
+                throw DecodingError.dataCorruptedError(in: container, debugDescription: "Unable to parse ISO8601 date")
+            }
+
+            return date
+        }
     }
 }
+
+public extension MastodonDecoder {
+    static let dateFormatter: ISO8601DateFormatter = {
+        let dateFormatter = ISO8601DateFormatter()
+
+        dateFormatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
+
+        return dateFormatter
+    }()
+}

Mastodon/Sources/Mastodon/Constants.swift

@@ -1,7 +0,0 @@
-// Copyright © 2020 Metabolist. All rights reserved.
-
-import Foundation
-
-public enum Constants {
-    public static let dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
-}