Add the json operator

Sources/AsyncWebSocketOperators/Operators.swift

@@ -60,3 +60,42 @@ extension AsyncStream where Element == AsyncWebSocketClient.ConnectionStatus {
   }
 }
 
+extension AsyncStream where Element: Sendable {
+  /// Transforms a stream of Element into a stream of Result of transformed Element or Error.
+  ///
+  /// It allows the stream to continue even upon failure when attempting to transform the element.
+  public func toResult<T: Sendable>(
+    transform: @Sendable @escaping (Element) throws -> T
+  ) -> AsyncStream<Result<T, any Error>> {
+    self
+      .map { element in
+        return Result { try transform(element) }
+      }
+      .eraseToStream()
+  }
+}
+
+extension AsyncStream where Element == AsyncWebSocketClient.Frame {
+  /// Attemps to decode into JSON if the frame is message.data or message.text.
+  public func json<T>(
+    _ type: T.Type
+  ) -> AsyncStream<Result<T, any Error>> where T: Codable, T: Sendable {
+    self
+      .on(\.message)
+      .toResult {
+        switch $0 {
+        case let .binary(data):
+          return try JSONDecoder().decode(T.self, from: data)
+        case let .text(string):
+          guard let data = string.data(using: .utf8) else {
+            throw NSError(
+              domain: "String To Data Conversion",
+              code: 0,
+              userInfo: ["reason": "Faield to convert string to data"]
+            )
+          }
+          return  try JSONDecoder().decode(T.self, from: data)
+        }
+      }
+  }
+}